Left without Charlie, on a high (7)
I believe the answer is:
excited
'a high' is the definition.
(thesaurus)
'left without charlie on' is the wordplay.
'left' becomes 'exited' ('exit' can be a synonym of 'leave').
'without' indicates putting letters inside ('without' can be similar in meaning to 'outside').
'charlie on' becomes 'c' (I am not sure about this - if you are sure you should believe this answer much more).
'exited' enclosing 'c' is 'EXCITED'.
Can you help me to learn more?
(Other definitions for excited that I've seen before include "in high spirits" , "Roused by strong emotion" , "With feelings roused, emotionally high" , "Aroused, enthused" , "Thrilled; agitated" .)