Fed is a verb. It's the past tense of feed.
'Fed' is the simple past. 'I have fed' is the present perfect. 'I had fed' is the past perfect. 'I will have fed' is the future perfect. 'I would have fed' is the conditional perfect.
"Input" can function as either a noun or a verb. As a noun, it refers to data or information fed into a system. As a verb, it means to enter data or information into a system.
The part of speech for this particular word is a noun.
part of speech
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.
The part of speech of "came" is a verb.
The part of speech for "breezy" is an adjective.