Wide boy out of order (5)
I believe the answer is:
roomy
'wide' is the definition.
(both can mean spacious)
'boy out of order' is the wordplay.
'boy' becomes 'roy' ().
'out of' is an insertion indicator (some letters on the outside of others).
'order' becomes 'om' (Order of Merit).
'roy' enclosing 'om' is 'ROOMY'.
(Other definitions for roomy that I've seen before include "Broad" , "Spaced-out" , "Not cramped" , "With ample space" , "Commodious" .)