Suss (verb)

1. To understand or figure out; to come to know or comprehend.
2. To investigate or find out about (something or someone) in a subtle or discreet way.

Origin:

20th century, probably a shortening of "suss out" which is a slang term.

Examples:

1. Can you suss out what's going on here?
2. He was trying to suss the situation before making a move.
3. It took me a while to suss what was going on, but I finally got it.
4. She was trying to suss out the truth of the matter.
5. I couldn't suss the meaning of the message he sent me.