Shock of opening tipple for a rum cocktail at start of the afternoon (6)
I believe the answer is:
trauma
'shock' is the definition.
(thesaurus)
'opening tipple for a rum cocktail at start of the afternoon' is the wordplay.
'opening' says to take the initial letters.
'for' means one lot of letters go next to another.
'cocktail' is an anagram indicator.
'at start of' suggests taking the first letters (I've seen 'at start' mean this).
The first letter of 'tipple' is 't'.
The initial letter of 'afternoon' is 'a'.
'a'+'rum'='arum'
'arum' with letters rearranged gives 'raum'.
't'+'raum'+'a'='TRAUMA'
'of' is the link.
(Other definitions for trauma that I've seen before include "Extreme shock" , "Physical injury - powerful emotional shock" , "Lasting shock or disturbance" , "Deeply-upsetting shock" , "Psychological 23" .)