Word: fuckheadedly
Part of speech: Adverb
Syllables: fuck
he
ad
ed
ly
Definition: In a fuckheaded manner; stupid, dim-witted
Morphemes:
Affix: fuck
Language: en
PoS: Adverb
Meaning: Used as an intensifier for the words "yes" and "no".
Affix: headed
Language: en
PoS: Verb
Meaning: Simple past tense and past participle of head; a projection out from one end; 
Affix: -ly
Language: en
PoS: Suffix
Meaning: Used to form adverbs from adjectives.