What defines an angleshoot?

[2handed]

I was trying to explain angleshooting to someone unfamiliar with poker, and wasn't sure the best way to distinguish where behaving deceptively at the table became unethical.

Among players it is obvious to most that taking a little bit of extra time or acting indecisive when you know immediately what your play will be is part of the game, but tricking someone into folding the winner by for instance intentionally declaring your hand incorrectly is problematic.

What is the defining characteristic of a deceptive behavior at the poker table that makes it unethical?