Pants on fire, missing point of argument (4)
I believe the answer is:
spat
'argument' is the definition.
(I've seen this before)
'pants on' is the wordplay.
'pants' becomes 'sp' (I can't explain this - if you can you should believe this answer much more).
'on' becomes 'at' (I've seen this in other clues).
'sp'+'at'='SPAT'
'fire missing point of' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for spat that I've seen before include "Old leg wear - brief quarrel" , "Pat's involved in petty quarrel" , "Petty quarrel or fight" , "Row; discharged" , "Unimportant quarrel between Pats" .)