Press over the moon, meeting with new cardinal (7)
I believe the answer is:
million
'cardinal' is the definition.
(similar in meaning)
'press over the moon meeting with new' is the wordplay.
'press over' becomes 'mill' (mill is a kind of press. I am not sure about the 'over' bit.).
'the moon' becomes 'Io' (moon of Jupiter).
'meeting with' is a charade indicator (letters next to each other).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'mill'+'io'+'n'='MILLION'
(Other definitions for million that I've seen before include "Large number" , "Ten thousand hundreds" , "A power of 1 Down" , "1,000,000" , "What mega means" .)