Swell can be a noun, adjective and verb.
Noun: A long series of ocean waves.
Adjective: Excellent, great.
Verb: To increase in size.
Normally red, swelled & bloodshot eyes, stuttering of speech, lack of concentration.
swelled My toe swelled up last night.
part of speech
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "lecturer" is a noun.