Honestly arranged surreptitiously (2,3,3)
I believe the answer is:
on the sly
'surreptitiously' is the definition.
(I've seen this before)
'honestly arranged' is the wordplay.
'arranged' is an anagram indicator (letters rearranged).
'honestly' anagrammed gives 'ON THE SLY'.
(Other definitions for on the sly that I've seen before include "With craft" , "Secretly or furtively" , "in private" , "Honestly (anag) - dishonestly" , "Done in an unpleasant and secret way" .)