adjective feebler, feeblest
1 Lacking physical strength, especially as a result of age or illness.
1.1 (of a sound) faint.
1.2 Lacking strength of character.
1.3 Failing to convince or impress.
Middle English from Old French fieble, earlier fleible, from Latin flebilis ‘lamentable’, from flere ‘weep’.
Every day, Bob makes what usually turns out to be a feeble attempt to use a “new” word in an effective sentence. The result is commonly ineffectual.