Expert, suitable, going round Delaware (5)
I believe the answer is:
adept
'expert' is the definition.
(adept is a kind of expert)
'suitable going round delaware' is the wordplay.
'suitable' becomes 'apt' (I've seen this before).
'going round' means one lot of letters goes inside another (some letters go around others).
'delaware' becomes 'DE' (standard two letter abbrev).
'apt' going around 'de' is 'ADEPT'.
(Other definitions for adept that I've seen before include "Having the required skills" , "Master" , "Thoroughly proficient" , "Practised" , "Proficient, skilled" .)