Noun
(countable) Something or someone in a group that is different or exceptional, that does not fit.
Synonym: odd man out
(uncountable) A visual puzzle where the guesser has to choose which word/picture/symbol etc. does not fit with the others.
Source: en.wiktionary.orgWe are a very close family, and I love them very much, but I'm definitely the odd one out. I live a completely different kind of life style. I always was different. I felt like a fish out of water; I really never knew who I was. Janet McTeer