kook vs odd man out

kook and odd man out both are nouns.

Word	Noun	Adjective	Verb	Adverb
kook	Yes	No	No	No
odd man out	Yes	No	No	No

As nouns, kook and odd man out are synonyms defined as:

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

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

kook (noun)	odd man out (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