twopenny-halfpenny vs threepenny

twopenny-halfpenny and threepenny both are adjectives.

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

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

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

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