cricketer vs fieldsman

cricketer and fieldsman both are nouns.

Word	Noun	Adjective	Verb	Adverb
cricketer	Yes	No	No	No
fieldsman	Yes	No	No	No

As nouns, fieldsman is a hyponym of cricketer; that is, fieldsman is a word with a more specific, narrower meaning than cricketer:

cricketer: an athlete who plays cricket
fieldsman: a member of the cricket team that is fielding rather than batting

Other hyponyms of cricketer include bowler, fielder, wicket-keeper.

cricketer (noun)	fieldsman (noun)
an athlete who plays cricket	a member of the cricket team that is fielding rather than batting