Bosses on one side of a coin (5)
I believe the answer is:
heads
'bosses' is the definition.
(I've seen this in another clue)
'on one side of a coin' is the wordplay.
'on one' becomes 'hea' (I am not sure about this - if you are sure you should believe this answer much more).
'side of' suggests removing the centre (I've seen 'sides of' mean this (only the letters on the sides remain)).
'a coin' becomes 'denarius' (I've seen this before).
'denarius' with its middle removed is 'ds'.
'hea'+'ds'='HEADS'
Can you help me to learn more?
(Other definitions for heads that I've seen before include "Leaders" , "Noddles; nuts" , "Coin-tossing call" , "Obverse of a coin" , "Obverse result of coin-tossing" .)