Issue them with the thing in question (4)
I believe the answer is:
'issue' is the definition.
(both can mean to give out or radiate)
'them with the thing in question' is the wordplay.
'them' becomes 'em' (abbreviation).
'with' says to put letters next to each other.
'the thing in question' becomes 'it' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
Can you help me to learn more?
(Other definitions for emit that I've seen before include "Give out or put forth" , "Conductor; telegram (US)" , "Issue" , "Exude" , "Sent" .)