Doctor grabs a second to catch his breath (4)
I believe the answer is:
gasp
'breath' is the definition.
(I know that gasp is a type of inhalation)
'doctor grabs a second' is the wordplay.
'doctor' becomes 'gp' (general practitioner).
'grabs' means one lot of letters goes inside another.
'second' becomes 's' (common abbreviation).
'a'+'s'='as'
'gp' placed around 'as' is 'GASP'.
'to catch his' is the 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 gasp that I've seen before include "Have trouble breathing" , "Say "ah"" , "First Greek letter" , "Short laboured intake of breath" , "Convulsive breath" .)