Man in Gwynedd yawning (4)
I believe the answer is:
eddy
'man' is the definition.
(I've seen this before)
'in gwynedd yawning' is the wordplay.
'in' indicates the answer is hidden within the clue.
'EDDY' can be found hidden inside 'gwynedd yawning'.
(Other definitions for eddy that I've seen before include "Whirling current" , "making the rounds?" , "Spin" , "Circle around" , "Fellow" .)