...have instinct about liberal excess (4)
I believe the answer is:
glut
'excess' is the definition.
(glut can mean an excess of something)
'have instinct about liberal' is the wordplay.
I cannot quite understand how this works, but
'liberal' could be 'l' (abbreviation) and 'l' is located in the answer.
'instinct' could be 'gut' and 'gut' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for glut that I've seen before include "Satiate" , "Excess, surfeit" , "An excessive supply, just too much" , "Excessive amount" , "Oversupply, plethora" .)