Buys up early opener with name and makes a profit (9)

'buys up' is the definition.
Although both the answer and definition are verbs in their -s form, I can't see how they can define each other.

'early opener with name and makes a profit' is the wordplay.
'opener' says to take the initial letters.
'with' says to put letters next to each other.
'name' becomes 'n' (common abbreviation e.g. on forms).
'and' is a charade indicator (letters next to each other).
'makes a profit' becomes 'grosses' (I can't justify this - if you can you should believe this answer much more).
The initial letter of 'early' is 'e'.
'e'+'n'+'grosses'='ENGROSSES'

Can you help me to learn more?