Scotsman in Kilmacolm Academy (3)
I believe the answer is:
mac
'scotsman' is the definition.
'in kilmacolm academy' is the wordplay.
'in' indicates the answer is hidden within the clue.
'MAC' can be found hidden inside 'kilmacolm academy'.
(Other definitions for mac that I've seen before include "one used in shower?" , "It may help you keep dry" , "Raincoat (colloq.)" , "Waterproof coat (colloq.)" , "Waterproof raincoat, in short" .)