Answer: feeblest

AnswerCrossword Clue
FEEBLESTMost frail
FEEBLESTLeast effective.
feeblestFailing to convince or impress
feeblest(of a sound) Faint
feeblestLacking physical strength, esp. as a result of age or illness
feeblestLacking strength of character
feeblestFEEBLE, very weak