Locums ringing English head on the blower (7)
I believe the answer is:
tempest
'blower' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'locums ringing english head on the' is the wordplay.
'locums' becomes 'temps' (I can't justify this - if you can you should believe this answer much more).
'ringing' means one lot of letters goes inside another.
'english' becomes 'E' (abbreviation).
'head on' suggests taking the first letters.
The first letter of 'the' is 't'.
'temps' going around 'e' is 'tempes'.
'tempes'+'t'='TEMPEST'
Can you help me to learn more?
(Other definitions for tempest that I've seen before include "Shakespeare play with storm scene" , "terrible blow" , "Cyclone" , "Bad weather" , "Violent storm (created by Shakespeare?)" .)