expression, i-adjective
not knowing what to do with oneself; feeling out of place; feeling one doesn't belong
Describes acute embarrassment, awkwardness, or a sense of not fitting in, often in social situations. The phrase is a fixed expression; the negative form ない is part of the idiom.
See also: 身の置き所がない
彼の前では身の置き所もない気持ちになった。
I felt so awkward in front of him that I didn't know what to do with myself.
初めてのパーティーで、身の置き所もなかった。
At my first party, I felt completely out of place.