Max, Mike and Jack hosted by a sober individual (2,4)
I believe the answer is:
at most
'max' is the definition.
(I've seen this in another clue)
'mike and jack hosted by a sober individual' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'and' means one lot of letters go next to another.
'jack' becomes 'OS' (Ordinary Seaman - jack can mean a sailor).
'hosted by' is an insertion indicator.
'a sober individual' becomes 'att' (I am not sure about this - if you are sure you should believe this answer much more).
'm'+'os'='mos'
'mos' placed into 'att' is 'AT MOST'.
Can you help me to learn more?
(Other definitions for at most that I've seen before include "Top whack!" , "Max?" , "Maximum possible" .)