All-round measurement (5)
I believe the answer is:
girth
'measurement' is the definition.
(thesaurus)
'all-round' is the wordplay.
I cannot quite see how this works, but
'round' could be 'girt' (girting is a kind of rounding) and 'girt' is present in the answer.
A single letter 'h' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for girth that I've seen before include "Distance around a person's body" , "Band around a horse's belly" , "Body's circumference around the middle" , "Distance round the middle" , "Measurement around the waist" .)