Indistinct, weak (5)
I believe the answer is:
faint
This clue is a double definition.
'indistinct' is the first definition.
(similar in meaning)
'weak' is the second definition.
(I know that weak can be written as faint)
(Other definitions for faint that I've seen before include "Hard to see" , "Swoon, pass out" , "Weak" , "Swoon - pale" , "Indistinct - pass out" .)