Story-teller in bar getting upset (4)
I believe the answer is:
liar
'story-teller' is the definition.
(I've seen this before)
'bar getting upset' is the wordplay.
'bar' becomes 'rail' (rail is a kind of bar).
'getting upset' is a reversal indicator.
'rail' backwards is 'LIAR'.
'in' acts as a link.
(Other definitions for liar that I've seen before include "One supplying pork pies" , "Person regularly 'economical with the truth'" , "Phoney" , "one telling a story" , "Person telling stories" .)