odd fellow vs kook

odd fellow and kook both are nouns.

Word	Noun	Adjective	Verb	Adverb
odd fellow	Yes	No	No	No
kook	Yes	No	No	No

As nouns, odd fellow and kook are synonyms defined as:

odd fellow and kook: someone regarded as eccentric or crazy and standing out from a group

Other synonyms of odd fellow include odd fish, odd man out, queer bird, queer duck.

odd fellow (noun)	kook (noun)
someone regarded as eccentric or crazy and standing out from a group	someone regarded as eccentric or crazy and standing out from a group