WordWeb Online

1. In favour of (an action or proposal etc.)
   "a pro vote"

1. An athlete who plays for pay
   - professional
    
2. An argument in favour of a proposal

1. In favour of a proposition, opinion, etc.

1. Substitute
    
2. In favour of

Derived forms: pros

Type of: argument, athlete, jock [N. Amer, informal], statement

Antonym: amateur, anti, con

Encyclopedia: Pro, John