without material strength or solidity

a flimsy fabric; a flimsy structure.

weak; inadequate; not effective or convincing

a flimsy excuse.

a thin kind of paper, esp. for use in making several copies at a time of an article, telegraphic dispatch, or the like, as in newspaper work.

a copy of a report or dispatch on such paper.

noun

debility , decrepitude , delicacy , delicateness , feebleness , fragileness , fragility , frailness , frailty , insubstantiality , puniness , unsoundness , unsubstantiality , weakliness , weakness