sink or swim
idiomPart ofswim
sink or swim — idiom
1. to be put in a situation where you must either succeed through your own efforts
1.idiom
Definition
to be put in a situation where you must either succeed through your own efforts or fail completely, without any help or support from others.
Example
The company gave the new sales team no training and simply left them to sink or swim on their own.
When Ada transferred to the advanced maths class, it was sink or swim — she had to learn the material quickly or fall behind.