“What did you do this weekend?” “I worked in the yard, 'mostly'.” [=I spent most of my time working in the yard]
The people at the concert were 'mostly' older people. [=most of the people were older people]
He gets around 'mostly' [='mainly, chiefly'] by car. [=he usually uses a car to get around]
(..) What do you think? I think it'll take years. Years I got. What I don't have are the rocks. Pickings are pretty slim in the yard. Pebbles, mostly. We're getting to be kind of friends, aren't we? Yeah, I guess. Can I ask you something? Why'd you do it? (..)1994 The Shawshank Redemption
(..) With what intention? I'm not sure. I was confused... ...drunk. I think... ...mostly I wanted to scare them. When they arrived, you went up to the house and murdered them. I was sobering up. I got back in the car and I drove home to sleep it off. (..)1994 The Shawshank Redemption