Give old teacher weapons for the great war? (10)
I believe the answer is:
armageddon
'war?' is the definition.
(I have seen 'Terrible war' mean 'armageddon' so perhaps 'war' could also mean 'armageddon')
'give old teacher weapons for the great' is the wordplay.
I cannot quite understand how this works, but
'old' could be 'aged' (similar in meaning) and 'aged' is found in the answer.
'teacher' could be 'don' (don can mean an academic - especially at Oxbridge) and 'don' is present in the answer.
The remaining letters 'arm' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for armageddon that I've seen before include "Apocalyptic battle" , "large-scale fighting" , "complete disaster" , "terminal struggle" , "large-scale conflict" .)