Is mother by way of being a wet blanket? (6)
I believe the answer is:
damper
'a wet blanket?' is the definition.
(I've seen this in another clue)
'is mother by way of' is the wordplay.
'is mother' becomes 'dam' (female parent of an animal).
'by way of' becomes 'per' (I've seen this in another clue).
'dam'+'per'='DAMPER'
'being' acts as a link.
(Other definitions for damper that I've seen before include "Moister" , "more soppy" , "bush bread" , "Piano string silencer" , "Negative influence - more moist" .)