Scrub part of tennis court (5)
I believe the answer is:
scour
'scrub' is the definition.
(I know that scrub can be written as scour)
'part of tennis court' is the wordplay.
'part of' indicates a hidden word.
'SCOUR' is hidden in the letters of 'tennis court'.
(Other definitions for scour that I've seen before include "Turn upside down" , "Scrub hard" , "search in detail" , "Clean by abrasion" , "Look high and low" .)