You call them anorexic .
Someone who is skinny.
To call someone slim shows approbation. Thin is neutral. Skinny is depreciatory.
A very thin, emaciated cow that may be close to death.
The phrase a thin line between love and means that both feelings are very intense and passionate. When a person is betrayed that can go from loving someone to hating someone very quickly.
Loud.
A thin, wispy beard that is hardly big enough to call a beard.
tenau is thin.
It is a compliment saying that someone is a fine, strong, young man. It wouldn't be used for someone very thin or someone who is unhealthy.
A Marxist
A comedian
linguist, polyglot