Moisten grass inhaled by doctor's other half (7)
I believe the answer is:
hydrate
'moisten' is the definition.
(I've seen this in another clue)
'by doctor's other half' is the wordplay.
'by doctor' becomes 'hyd' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'other' becomes 'separate' (associated in meaning).
'half' indicates taking half.
'separate' halved is 'rate'.
'hyd'+'rate'='HYDRATE'
'grass inhaled' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for hydrate that I've seen before include "Give water" , "compound" , "Apply water" , "Thready (anag.)" , "Moisturise" .)