goddamn vs goddamned

goddamn and goddamned both are adjectives.

Word	Noun	Adjective	Verb	Adverb
goddamn	No	Yes	No	Yes
goddamned	No	Yes	No	Yes

As adjectives, goddamn and goddamned are synonyms defined as:

Other synonyms of goddamn include blame, blamed, blasted, blessed, damn, damned, darned, deuced, goddam, infernal.

As adverbs, goddamn and goddamned are synonyms defined as:

goddamn and goddamned: expressing anger, despair, frustration, approval, or surprise

Other synonyms of goddamn include goddam.

goddamn (adjective)	goddamned (adjective)
used as expletives	expletives used informally as intensifiers
expletives used informally as intensifiers

goddamn (adverb)	goddamned (adverb)
expressing anger, despair, frustration, approval, or surprise	expressing anger, despair, frustration, approval, or surprise