Having a bit of an impediment, not strong (3)
I believe the answer is:
dim
'strong' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I can't see?
'having a bit of an impediment not' is the wordplay.
'DIM' is hidden within the letters.
However, I am unsure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for dim that I've seen before include "Not bright or distinct" , "Unintelligent; badly lit" , "Providing little light" , "Not bright, literally or mentally" , "Gloomy; dull" .)