the deep end

/ðə dˈiːp ˈɛnd/

the deep end

a situation that is very difficult because one is not prepared to deal with it

the section of a swimming pool where the water is at its deepest point

Examples

1. Teachers are thrown in the deep end when they first start teaching.

2. I had never worked in sales before, but my boss threw me in at the deep end, and I learned quickly.

3. Every time it was to better my situation, and it was always scary, and I just went into the deep end, you know?

4. My dad went off the deep end when he found out what I'd done.