Feeble fellows, but maybe not easy to kill (5)
I believe the answer is:
weeds
'kill' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for weeds that I've seen before include "Are they worn by widows in the garden?" , "Black garments once worn by widows" , "Unwanted plants" , "mourning clothes" , "Wild plants; mourning garb" .)