He plans to 'thin' (out) the young carrots in the garden. [=to remove some of them so that there is more room between the remaining carrots]
His hair is a little 'thin' on top. = He's a little 'thin' on top. [=he does not have a lot of hair on the top of his head]
The bank's decision to raise rates could be 'the thin end of the wedge'. [=many other banks may also decide to raise rates]
(..) - Good morning. Mom! Dad! MR. MCFLY: Hit your head? MRS. MCFLY: Are you okay? You guys look great. Mom, you look so thin. Why, thank you, Marty. George! Good morning, sleepyhead. MRS. MCFLY: Good morning, kids. DAVID AND LINDA: 'Morning. LINDA: Marty, I almost forgot. (..)1985 Back to the Future
(..) My name is Lorraine. LORRAINE: Lorraine Baines? MARTY: Yeah. But you're... You're so... You're so thin! Just relax, Calvin. You got a big bruise on your head. Where are my pants? Over there... ...on my hope chest. (..)1985 Back to the Future