Delighted, extremely proud about legal agreement (7)
I believe the answer is:
pleased
'delighted' is the definition.
(similar in meaning)
'extremely proud about legal agreement' is the wordplay.
'extremely' means to remove the middle letters (only the extremes of the word are used).
'about' indicates putting letters inside.
'legal agreement' becomes 'lease' (I've seen this in another clue).
'proud' with its middle removed is 'pd'.
'pd' placed around 'lease' is 'PLEASED'.
(Other definitions for pleased that I've seen before include "Glad" , "Content" , "Gratified" , "Happy, satisfied" , "Well satisfied" .)