feeble
adj.adj. very weak and lacking physical strength or power. You can also use it to describe an excuse or argument that is not convincing.
adj. lacking physical strength, especially as a result of age or illness; failing to convince or achieve an intended effect.
The old man gave a feeble wave as we drove away.
The manager was not impressed by the employee's feeble excuse for arriving two hours late to the meeting.
Despite the patient's feeble condition, she managed to whisper a few words of gratitude to the medical staff before falling back into a deep sleep.
Etymology tree Anglo-Norman feblebor. Middle English feble English feeble From Middle English feble, from Anglo-Norman feble (“weak, feeble”) (compare French faible), from Latin flēbilis (“tearful, mournful, lamentable”) by dissimilation, from fleō (“to weep, cry”), ultimately from Proto-Indo-European *bʰleh₁-. Doublet of foible.
Often used predicatively after 'feel' or 'look', or attributively to modify nouns like 'excuse', 'attempt', or 'effort'.