Regulates ways without estimate (9)
I believe the answer is:
moderates
'regulates' is the definition.
(moderating is a kind of regulating)
'ways without estimate' is the wordplay.
'ways' becomes 'modes' ('mode' can be a synonym of 'way').
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'estimate' becomes 'rate' (I've seen this in other clues).
'modes' going around 'rate' is 'MODERATES'.
(Other definitions for moderates that I've seen before include "People who don't have extreme views, say about politics" , "chairs" .)