One keen on discipline in term, a worrying time (8)
I believe the answer is:
martinet
'one keen on discipline' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'in term a worrying time' is the wordplay.
'worrying' indicates an anagram.
'time' becomes 't' (abbreviation).
'in'+'term'+'a'='interma'
'interma' with letters rearranged gives 'martine'.
'martine'+'t'='MARTINET'
Can you help me to learn more?
(Other definitions for martinet that I've seen before include "Trite man becomes a tyrant" , "A strict disciplarian" , "Tyrant, one who demands strict obedience" , "Strict disciplinarian - met train (anag)" , "Rigorous figure" .)