Impress trendy whisky-maker no end (6)
I believe the answer is:
instil
'impress' is the definition.
(I've seen this before)
'trendy whisky-maker no end' is the wordplay.
'trendy' becomes 'in'.
'whisky-maker' becomes 'still' (device for distilling alcoholic drinks).
'no end' means to remove the last letter.
'still' with its final letter taken away is 'stil'.
'in'+'stil'='INSTIL'
(Other definitions for instil that I've seen before include "Mentally fix" , "Put in drop by drop" , "Gradually establish something in a person's mind" , "Introduce gradually into mind, say ideas" , "Plant gradually into the mind" .)