Afraid and Weak-kneed

Afraid adjective - Filled with fear or dread.

Weak-kneed and afraid are semantically related In some cases you can use "Weak-kneed" instead an adjective "Afraid".

Weak-kneed adjective - Lacking strength of will or character.

Afraid and weak-kneed are semantically related in fearful topic. Sometimes you can use "Afraid" instead an adjective phrase "Weak-kneed", if it concerns topics such as alarmed.