Generously accommodating a chap who's out of order (5)
I believe the answer is:
roomy
'generously accommodating a chap' is the definition.
I can't tell whether this defines the answer.
'who's out of order' is the wordplay.
'who's' becomes 'roy' (I can't explain this - if you can you should believe this answer much more).
'out of' indicates putting letters inside (some letters on the outside of others).
'order' becomes 'om' (Order of Merit).
'roy' placed around 'om' is 'ROOMY'.
Can you help me to learn more?
(Other definitions for roomy that I've seen before include "so wide" , "Spacious, can swing a cat in it" , "Spaced-out" , "Capacious" , "Without cramping" .)