Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Weak-kneed \Weak"-kneed`\, a.
Having weak knees; hence, easily yielding; wanting
resolution.
--H. James.
Wiktionary
a. 1 (context figuratively English) Lacking will power or strength of character; timid. 2 (context literally English) (&lit week kneed English) alt. 1 (context figuratively English) Lacking will power or strength of character; timid. 2 (context literally English) (&lit week kneed English)
WordNet
adj. lacking will power or resolution; "the role of the dissenter is not for the weak-kneed"
Usage examples of "weak-kneed".
Temple and the Holy of Holies, he found himself quaking, as weak-kneed as the most superstitious peasant as he paused for a moment before the great screen of silver latticework that concealed the Sanctorium of the Eye.
That might have been the case with the last king, known to be as lionhearted as he was called, but with his weak-kneed baby brother?
There's plenty of hill-grubbing savages that carve up their own faces to frighten weak-kneed recruits like you, Gullstream.
Beauty Smith was known far and wide as the weakest of weak-kneed and snivelling cowards.
Though, speaking without prejudice and with no wish to be offensive, if I had had a model who wasn't a weak-kneed, jelly-backboned son of Belial, I could have got the darned thing finished without having to have another sitting.
She stood on her tiptoes and brushed her mouth across his in a kiss that was so achingly sweet that he thought for one paralyzingly weak-kneed moment he just might faint.