The phrase "holds own" refers to being capable of handling a situation or standing up for oneself against opposition. Antonyms for this phrase would reflect an inability or lack of competence to do so. These antonyms could include "incompetent," "weak," "unsure," "insecure," "vulnerable," "dependent," "ineffective," "inefficient," "inept," and "impotent." Alternatively, phrases that could be considered antonyms for "holds own" might include "gives in," "falters," "succumbs," "fails," "breaks down," "collapses," "loses footing," or "crumbles." These terms all suggest a lack of strength or control in the face of challenge or adversity.