Tired and dehydrated, suppressing cries of pain (6)
I believe the answer is:
drowsy
'tired' is the definition.
(I've seen this before)
'dehydrated suppressing cries of pain' is the wordplay.
'dehydrated' becomes 'dry' (similar in meaning).
'suppressing' is an insertion indicator.
'cries of pain' becomes 'ows' (I've seen this in another clue).
'dry' placed around 'ows' is 'DROWSY'.
'and' is the link.
(Other definitions for drowsy that I've seen before include "Disinclined to stay awake" , "Sleepy, somnolent" , "Sleepy, lethargic" , "Comatose" , "Torpid" .)