Send forth or send back help in time (7)
I believe the answer is:
radiate
'send forth' is the definition.
(I've seen this in another clue)
'send back help in time' is the wordplay.
I cannot quite see how this works, but
'time' could be 'ad' (AD, Anno Domini, as opposed to BC, Before Christ) and 'ad' is located in the answer.
This explanation may well be incorrect...
'or' acts as a link.
Can you help me to learn more?
(Other definitions for radiate that I've seen before include "Emit rays; diverge" , "Travel from centre in all directions" , "A tirade (anag)" , "Beam brightly, spread heat" , "Emit light/heat" .)