lexicow

dissimilarvsunalike

Dissimilar and unalike both mean 'not alike', and they are very close — but each leans a shade differently. Dissimilar means different in nature or kind: other at the root, the formal and often technical word (think 'dissimilar metals'). Unalike means sharing no resemblance, failing to correspond: the plainer word, stressing that nothing in the one matches the other. Same idea — not the same — but dissimilar points at a difference of kind, unalike at a simple lack of likeness.

dissimilar

Two dissimilar metals — a warm copper rod and a cool zinc rod — in one beaker; join them with a wire and the difference does work: current runs, bubbles rise, the zinc corrodes. Their difference is real enough in kind to react.

/dɪˈsɪmələr//dɪˈsɪmɪlə/·adjective
vs
unalike

A struck tuning fork rings, and only the fork of the very same length answers, singing along on its own; the unalike forks stand dead still, giving nothing back. No matching likeness, no response.

/ˌʌnəˈlaɪk//ˌʌnəˈlaɪk/·adjective

These are unusually close synonyms, so the axis is fine but real, and the physics behind each word marks it. Dissimilar is dis- ('not') plus the Latin similis ('like'): a difference in composition or kind, real enough that two dissimilar metals in an electrolyte will set up a current and corrode. Unalike is the plain un- ('not') plus 'alike': a lack of correspondence, like tuning forks of different lengths — strike one and the unalike ones never answer. So dissimilar leans on being other in kind; unalike on sharing no matching likeness.

What each means

dissimilar

Dissimilar means unlike in nature or kind — different not by a shade but at the root. It is built from dis-, 'not', and the Latin similis, 'like', the same root as 'similar' and 'resemble'. The word leans formal and is often technical: engineers warn that dissimilar metals in contact will corrode, because the gap between them is real enough to drive a current. To call two things dissimilar is to say they are other in kind, and usually that the contrast is plain enough to distinguish at a glance.

unalike

Unalike means not alike — sharing no resemblance, failing to correspond. It is built plainly from un-, 'not', and 'alike', and it usually describes two things set side by side that simply do not match: two unalike siblings, two unalike halves. Where dissimilar leans formal and technical, unalike is the plainer word, and it stresses the absence of any answering likeness — nothing in the one echoes the other. It almost always follows what it describes ('the two are unalike') rather than standing before a noun.

At a glance

dissimilarunalike
Meaningdifferent in nature or kindsharing no resemblance
Emphasisother at the root; a real difference of kindno matching likeness; failure to correspond
Registerformal, often technicalplainer, more everyday
Often withdissimilar to / dissimilar metalsutterly / completely unalike
RootLatin similis, 'like' (dis- + similar)plain English: un- + alike
Exampletwo chemically dissimilar mineralstwo siblings, utterly unalike

How to remember the difference

Picture two benches. Two metals — copper and zinc — in one beaker, so different in kind that wiring them together makes a current and eats one away: that difference at the root is dissimilar. A struck tuning fork whose only answer comes from the one fork of the same length, while the rest stand silent: that lack of any matching likeness is unalike. Both mean 'not the same'; dissimilar stresses a difference of kind, unalike a simple absence of resemblance. For composition or category, reach for dissimilar; for 'they just don't match', reach for unalike.

Examples

dissimilar

  • The two minerals are chemically dissimilar, however alike they look.
  • Her method is wholly dissimilar to her mentor's.
  • Dissimilar metals in contact will corrode over time.

unalike

  • The twins are physically alike but temperamentally unalike.
  • However you compare them, the two accounts are utterly unalike.
  • Their tastes are so unalike that they never agree on a film.

They are nearly interchangeable, and in everyday use you can swap them. The fine tell: dissimilar leans on a difference of nature or kind (and carries the technical 'dissimilar metals'), while unalike leans on a plain lack of resemblance or correspondence. Dissimilar is the more formal choice; unalike is plainer and almost always comes after the noun ('the two are unalike').

FAQ

What is the difference between dissimilar and unalike?
Both mean 'not alike'. Dissimilar stresses a difference in nature or kind and is more formal (as in 'dissimilar metals'); unalike stresses a simple lack of resemblance or correspondence and is the plainer word. The gap between them is small but real.
Are dissimilar and unalike synonyms?
Yes, very close ones — both mean not the same, with no opposition between them. They differ only in shade and register: dissimilar leans formal and 'other in kind', unalike leans plain and 'no matching likeness'.
Can I use them interchangeably?
Usually, yes. But choose dissimilar for a difference of kind or in technical contexts ('dissimilar materials'), and unalike for an everyday 'they just don't match', especially after the noun ('the two are unalike').
Which word is more formal?
Dissimilar. It suits academic and technical writing and takes the preposition 'to' (dissimilar to). Unalike is plainer and more conversational.
Does 'not dissimilar' mean similar?
Yes — 'not dissimilar to' is a litotes (understatement) that actually means 'quite similar'. It is a useful, slightly formal way to hedge a comparison.
How do you pronounce them?
Dissimilar is /dɪˈsɪmələr/, stressed on the second syllable (dis-SIM-i-lar). Unalike is /ˌʌnəˈlaɪk/, stressed on the last (un-a-LIKE).

Related synonyms

dissimilar — full entryunalike — full entry← All synonyms