Drinks up causing bad temper (5)
I believe the answer is:
strop
'bad temper' is the definition.
(I've seen this before)
'drinks up' is the wordplay.
'drinks' becomes 'ports' (port is a kind of drink).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'ports' back-to-front is 'STROP'.
'causing' acts as a link.
(Other definitions for strop that I've seen before include "Outburst" , "Sharpen on piece of leather" , "Fit of bad temper" , "temper tantrum" , "Bad mood; sharpen" .)