noun, used as a suffix
Attaches to nouns to describe a person's physical or mental stance, often in set phrases like 構え腰 (ready stance) or 及び腰 (hesitant attitude).
彼はいつも及び腰で、なかなか決断できない。
He is always hesitant and can't make decisions easily.
彼は強腰で交渉に臨んだ。
He entered the negotiation with a firm stance.
Derived from 腰 (こし, 'hip, waist'), extended metaphorically to mean one's stance or attitude, as the hips are central to body posture.