Verb (1-dan, intransitive)
1. to become known; to come to light; to be discovered
2. to be known; to be understood
usu. in the negative
あの人の強さは底がしれない。There's no telling how deep that person's strength goes.
3. to clearly not amount to much; to be insignificant
一人の力なんてしれたものだ。One person's strength doesn't amount to much.
4. to be evident; to be obvious; to go without saying
as 知れたこと
5. to be very intense (of worry, hope, etc.); to be severe
as どんなに…か知れない, どれほど...か知れない, etc.
彼には何度助けられたかしれない。I've lost count of how many times he has helped me.