Tranquil! The others almost drunk (7)
I believe the answer is:
restful
'tranquil' is the definition.
(I've seen this before)
'the others almost drunk' is the wordplay.
'the others' becomes 'rest' (I've seen this before).
'almost drunk' becomes 'ful' (I can't explain this - if you can you should believe this answer much more).
'rest'+'ful'='RESTFUL'
Can you help me to learn more?
(Other definitions for restful that I've seen before include "Calm" , "Sedative" , "Soothing is required" , "Quiet, soothing" , "Still - calming" .)