Happy to find rental contract, occupying vacant pad (7)
I believe the answer is:
pleased
'happy' is the definition.
(similar in meaning)
'rental contract occupying vacant pad' is the wordplay.
'rental contract' becomes 'lease' (I've seen this before).
'occupying' indicates putting letters inside (inserted letters occupy or enter the word).
'vacant' suggests removing the centre (a vacant or emptied out form of the word).
'pad' with its centre removed is 'pd'.
'lease' placed within 'pd' is 'PLEASED'.
'to find' acts as a link.
(Other definitions for pleased that I've seen before include "Euphoric" , "Well satisfied" , "like Punch?" , "Happy, satisfied" , "Grateful, delighted" .)