站不住腳 have not a leg to stand on; be done for; be untenable; cannot be justified; cannot hold one's ground; cannot hold water; (what you said) doesn't hold water.; groundless; ill-founded; ill-grounded; impossible to defend; unable to consolidate one's position; unable to get a footing; unable to stand [maintain] one's ground 他的這種理論是站不住腳的。 he hasn't a leg to stand for this theory of his. 你的理由站不住腳。 your argument is ill-founded