|Origin:||Old English un-, on-, from and- 'against'|
1XX [in adjectives, adverbs, and nouns]
used to show a negative, a lack, or an opposite [= not]:
2 [in verbs]
used to show an opposite of a particular action:
to undress (=to take your clothes off)
Have you unpacked yet (=taken your things out of your suitcase)?
I heard Lila unlock the front door.