Show form to tradesmen (11)
I believe the answer is:
demonstrate
'show' is the definition.
(I know that show can be written as demonstrate)
'form to tradesmen' is the wordplay.
'form' is an anagram indicator (another form of the letters).
'to'+'tradesmen'='totradesmen'
'totradesmen' is an anagram of 'DEMONSTRATE'.
(Other definitions for demonstrate that I've seen before include "Review" , "Make a public protest" , "English floozies returning, led by villainous character" , "March" , "Present" .)