Unpack is a verb.
Verb
The past tense of unpack is unpacked.
The phrase "Unpack immediately." is an imperative sentence. The understood subject is "you," so the sentence means "(You) unpack immediately." It is a command.
The part of speech for this particular word is a noun.
part of speech
Undress, unpack and unpaid.
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.