flimsiest
flim-si-est
adjective
The superlative form of flimsy; most easily broken, torn, or inadequate.
"He offered the flimsiest excuse for being late."
Thesaurus
Synonyms: unconvincing, flimsy, unpersuasive, weak, insubstantial, onionskin, insignificant, slight, unimportant, fragile, tenuous, thin
Antonyms: convincing