Forefathers - Forebears
Gentleman's agreement - Agreement based on trust.
Girls (for adults) - Women
Housewife - Homemaker
Manpower - Labour force / Human resources
Man / Mankind - Humanity
Man-made - Artificial
Man in the street / common man - Average citizen
Right-hand man - Chief assistant
Sportsmanship - Fairness / Sense of fair play
We will all be 'sering' before we know it.)