1.
If you describe something as ~, you mean that it is shaped like a hook.
He was thin and tall, with a ~ nose.
ADJ: usu ADJ n
2.
If you are ~ on something, you enjoy it so much that it takes up a lot of your interest and attention. (INFORMAL)
Many of the leaders have become ~ on power and money...
ADJ: v-link ADJ, oft ADJ on n
3.
If you are ~ on a drug, you are addicted to it. (INFORMAL)
He spent a number of years ~ on cocaine, heroin and alcohol.
ADJ: v-link ADJ, oft ADJ on n