From Longman Dictionary of Contemporary Englishthe odd man/one outthe odd man/one outBritish English someone or something that is different from the rest of the group or not included in it Which shape is the odd one out? I was always the odd one out at school. → odd
Examples from the Corpus
the odd man/one out• Which of the following grape varieties is the odd one out? 4.• At each stage of the story, Britain has been the odd man out.• Why is it always the odd man out?• Others are widowed or divorced, and hate being the odd one out among friends who are all couples.• Unless Spencer is traded, the latter seems to be the odd man out despite showing improvement in the preseason.• He was the odd one out in a gifted family.• I was always the odd man out in my class at school.• And Joe Bowie remains the odd man out, uncoupled at the end. 