large vs biggish

large is a noun but biggish is not a noun.

Word	Noun	Adjective	Verb	Adverb
large	Yes	Yes	No	Yes
biggish	No	Yes	No	No

large (noun)	biggish (noun)
a garment size for a large person

large (adjective)	biggish (adjective)
above average in size or number or quantity or magnitude or extent	somewhat large
having broad power and range and scope
conspicuous in position or importance
generous and understanding and tolerant
in an advanced stage of pregnancy
ostentatiously lofty in style
fairly large or important in effect; influential

large (adverb)	biggish (adverb)
with the wind abaft the beam
at a distance, wide of something (as of a mark)
in a boastful manner