Suitable, proper, strikingly appropriate, pertinent, right for the occasion.
Etymology: 1620s, from Latin appositus, "contiguous, neighboring".
Although 'opposite' looks and sounds almost identical, both the meaning and the word origin (oppositer, to place against) are different.
Now for a bit of a puzzle:
'Apposable' means "capable of being placed side by side (brought into apposition)"; this word's definition more clearly ties back to the Latin origin mentioned above. 'Opposable' means "can be placed opposite something".
So, human thumbs are both opposable and apposable: the thumb is opposite the fingers, and it can also touch (be placed next to) each finger. I think you could have an opposable thumb that was too far away or too stiff to be placed next to the fingers; likewise human fingers are all apposable with each other, even though they aren't opposable.
...At least, that's my interpretation. But, some dictionaries list 'apposable' as an alternate spelling of 'opposable', with no distinction between the two terms. The majority of internet search results for 'apposable' lean this direction.
What I suspect is that the two terms were distinct at some point in the past, and over time the similar-sounding words blurred together and the more common definition prevailed. However, I have no proof for this. Can anyone clarify?
