This compiler's describing Queen, pure and simple (4)
I believe the answer is:
mere
'pure and simple' is the definition.
(I've seen this before)
'this compiler's describing queen' is the wordplay.
'this compiler' becomes 'me' (the person who is writing these clues).
'describing queen' becomes 're' (Royal Excellency**).
'me'+'re'='MERE'
(Other definitions for mere that I've seen before include "Lake, pond (poetic)" , "Without additions or modifications" , "Pond - pure and simple" , "a drop of water" , "Nothing more than a small pond" .)