threepenny vs twopenny-halfpenny

threepenny and twopenny-halfpenny both are adjectives.

Word	Noun	Adjective	Verb	Adverb
threepenny	No	Yes	No	No
twopenny-halfpenny	No	Yes	No	No

As adjectives, threepenny and twopenny-halfpenny are synonyms defined as:

Other synonyms of threepenny include sixpenny, tuppeny, two-a-penny, twopenny.

threepenny (adjective)	twopenny-halfpenny (adjective)
of trifling worth	of trifling worth
used of nail size; 1 1/4 in long