Gauge (8)
'gauge' is the definition.
(I know that gauge can be written as estimate)
This is the entire clue.
(Other definitions for estimate that I've seen before include "Make approximate judgement of size or amount" , "Assess value" , "Gauge - approximation" , "Form opinion of - tea times (anag)" , "Calculate roughly" .)
'gauge' is the definition.
(I know that gauge is a more specific form of the action measure)
This is all the clue.
(Other definitions for measure that I've seen before include "Ascertain dimensions" , "Gauge" , "The size of a dance" , "Take dimensions of" , "Portion" .)