a brainteaser or puzzle
He can never understand physics, it always perplexes him.
If someone perplexes someone else, they puzzle them.
To make perplex a noun you add -er to make "Perplexer" which is one who perplexes.
mixes up with, take for, muddles with, bewilders, puzzles, baffles, perplexes, mystifies, flusters
to confuse or trouble with unertainty or doubt
No, perplex is a verb. The noun form is perplexer, one who perplexes
People
Many people in Israel have something to play with.
They keep something or, something out.
An association of people who have something in common
When people distill something in a paraphrase, they are condensing important points.
The act of trying to know something about people is known as investigating.