Test for blonde tips (5)
I believe the answer is:
probe
'test' is the definition.
(probe can mean to test or experiment)
'for blonde tips' is the wordplay.
'for' becomes 'pro' (as in being 'pro' or in favour of something).
'tips' means to remove the middle letters (just the outer letters of the world).
'blonde' with its centre taken out is 'be'.
'pro'+'be'='PROBE'
(Other definitions for probe that I've seen before include "Spacecraft; investigation" , "sound" , "(Crime) investigation" , "Examine searchingly" , "Inquiry" .)