Meaning:
"To be thrown in at the deep end" means to be given a difficult or challenging task or situation without any prior training or preparation. It implies being thrust into a situation where one is expected to perform well despite lacking the necessary skills or experience.
Example:
* "I was thrown in at the deep end when they asked me to lead the project, having only joined the company a week ago."
Origin:
The idiom is a metaphor referencing the experience of learning to swim. A beginner is usually taught to swim in shallow water before being allowed to venture into deeper areas. Being "thrown in at the deep end" implies skipping the shallow end and forcing someone to learn by doing, even if they're not yet ready.