Quarrels difficult to deal with, leader being put down (5)
I believe the answer is:
tiffs
'quarrels' is the definition.
(tiff is a kind of quarrel)
I don't understand how the rest of the clue works.
(Other definitions for tiffs that I've seen before include "Spats" , "Small quarrels" , "Arguments" , "Petty quarrels" , "Huffs; squabbles" .)