master / leader / teacher (in a primary school)

a title given to lawyers and notaries public in France, Belgium, and Canada

the person in charge of the team of waiters in a restaurant or hotel / a headwaiter; major-domo

swimming instructor, swimming trainer, swimming coach / lifeguard (attendant employed to save swimmers in trouble or near drowning)

dog handler

client, customer, user / project leader, process manager / contracting authority

high altar

(military, nautical) quartermaster

female equivalent of maître-nageur

(archaic) dandy, coxcomb