Upset seen during tactless tirade (4)
I believe the answer is:
stir
'upset' is the definition.
(thesaurus)
'during tactless tirade' is the wordplay.
'during' says the answer is hidden in the clue.
'STIR' can be found hidden inside 'tactless tirade'.
'seen' acts as a link.
(Other definitions for stir that I've seen before include "Budge" , "Wake; disturbance" , "Whisk or whip" , "Wake up - prison" , "Ladies' underwear" .)