Have a go at tango, mostly unoccupied (7)
I believe the answer is:
attempt
'have a go at' is the definition.
(I've seen this in another clue)
'tango mostly unoccupied' is the wordplay.
'tango' becomes 'att' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'mostly' means to remove the last letter (most but not all of the word).
'unoccupied' becomes 'empty' (similar in meaning).
'empty' with its final letter taken off is 'empt'.
'att'+'empt'='ATTEMPT'
Can you help me to learn more?
(Other definitions for attempt that I've seen before include "Endeavor, try" , "Essay" , "Stab" , "Shot" , "Try to climb (a peak)" .)