flimsy

adj. (-ier, -iest) 1 insubstantial, rickety (flimsy structure). 2 (of an excuse etc.) Unconvincing. 3 (of clothing) thin.  flimsily adv. Flimsiness n. [origin uncertain]

superl. Weak; feeble; limp; slight; vain; without strength or solidity; of loose and unsubstantial structure; without reason or plausibility; as, a flimsy argument, excuse, objection.