Head of Chinese State Intelligence is yawning (9)
I believe the answer is:
cavernous
'is yawning' is the definition.
(I've seen this in another clue)
'head of chinese state intelligence' is the wordplay.
'head of' suggests taking the first letters.
'state' becomes 'aver' (both can mean to declare).
'intelligence' becomes 'nous' (I've seen this before).
The first letter of 'chinese' is 'c'.
'c'+'aver'+'nous'='CAVERNOUS'
(Other definitions for cavernous that I've seen before include "Gaping" , "of large underground chambers" , "Roomy" , "like a big pit" .)