expression, i-adjective
unprincipled; inconstant; unscrupulous
Describes a person who lacks firm principles, easily changes their stance, or acts without moral scruples. Often used in negative evaluations of character.
See also: 無節操
彼は節操がなくて、すぐに意見を変える。
He is unprincipled and changes his opinion right away.
そんな節操がない行動
Such unscrupulous behavior is unacceptable.
無節操 is a noun or na-adjective meaning 'lack of principles' or 'unscrupulousness', while 節操がない is a phrase literally meaning 'has no principles'. The meaning is similar, but 節操がない is more colloquial and descriptive.
Compound of 節操 (principles, fidelity) and the negative form of ある (to exist), literally 'to have no principles'. The exact historical derivation is uncertain, but the phrase is a straightforward combination of these elements.