twopenny-halfpenny vs sixpenny

twopenny-halfpenny and sixpenny both are adjectives.

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

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

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

twopenny-halfpenny (adjective)	sixpenny (adjective)
of trifling worth	of trifling worth