Most hesitant mum so far cradling son (6)
I believe the answer is:
shyest
'most hesitant' is the definition.
(shy can mean hesistant)
'mum so far cradling son' is the wordplay.
'mum' becomes 'sh' (both are used to tell someone to be quiet).
'so far' becomes 'yet' (both can mean 'until now').
'cradling' is an insertion indicator.
'son' becomes 's' (genealogical abbreviation for son).
'yet' going around 's' is 'yest'.
'sh'+'yest'='SHYEST'
(Other definitions for shyest that I've seen before include "Most bashful or self-conscious" , "Most retiring" , "Most diffident" , "Most timid" , "withdrawn the most" .)