Patent happening to get one director on board (7)
I believe the answer is:
evident
'patent' is the definition.
(I've seen this before)
'happening to get one director on board' is the wordplay.
'happening' becomes 'event' (I've seen this before).
'to get' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'director' becomes 'd'.
'on board' means one lot of letters goes inside another.
'event' placed around 'i' is 'evient'.
'evient' going around 'd' is 'EVIDENT'.
(Other definitions for evident that I've seen before include "Conspicuous" , "Comprehensible - manifest" , "Visible - plain" , "Obvious, quite apparent" , "'Plain, apparent (7)'" .)