fella vs lad

fella and lad both are nouns.

Word	Noun	Adjective	Verb	Adverb
fella	Yes	No	No	No
lad	Yes	No	No	No

As nouns, fella and lad are synonyms defined as:

Other synonyms of fella include blighter, bloke, chap, cuss, feller, fellow, gent.

fella (noun)	lad (noun)
a boy or man	a male child (a familiar term of address to a boy)
	a boy or man