Drink with timid guards (6)
I believe the answer is:
shandy
'drink' is the definition.
(I know that shandy is a type of drink)
'with timid guards' is the wordplay.
'with' becomes 'and'.
'timid' becomes 'shy' (synonyms).
'guards' is an insertion indicator (inserted letters are guarded).
'and' inserted inside 'shy' is 'SHANDY'.
(Other definitions for shandy that I've seen before include "Weakly-alcoholic drink" , "Beer/lemonade drink" , "Lemonade-beer drink" , "Light beer" , "mixed drink" .)