loggerhead vs pudden-head

loggerhead and pudden-head both are nouns.

Word	Noun	Adjective	Verb	Adverb
loggerhead	Yes	No	No	No
pudden-head	Yes	No	No	No

As nouns, pudden-head is a hypernym of loggerhead; that is, pudden-head is a word with a broader meaning than loggerhead:

loggerhead: a stupid person; these words are used to express a low opinion of someone's intelligence
pudden-head: a person who is not very bright

Other hypernyms of loggerhead include dolt, dullard, pillock, poor fish, pudding head, stupe, stupid, stupid person.

loggerhead (noun)	pudden-head (noun)
very large carnivorous sea turtle; wide-ranging in warm open seas	a person who is not very bright
a stupid person; these words are used to express a low opinion of someone's intelligence