Afternoon repast (3)
(Other definitions for high tea that I've seen before include "Early-evening meal" , "A lofty kind of evening meal" , "Late afternoon meal which includes a cooked dish" , "Late-afternoon meal" , "Early evening meal" .)
'afternoon repast' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tea that I've seen before include "Refreshment" , "Beverage from leaves" , "TREE" , "Strangely, one may eat this drink" , "Afternoon or evening meal" .)