For catching something physically:
* Attraper: This is the most general word for "catch" and can be used for catching a ball, a thief, or even a cold.
* Saisir: This implies a more forceful or sudden catching, like grabbing something quickly.
For catching something figuratively:
* Attraper: This can also be used for catching someone's attention or catching a feeling.
* Comprendre: This translates to "understand" and can be used for catching someone's meaning or understanding a joke.
Examples:
* J'ai attrapé le ballon. (I caught the ball.)
* La police a attrapé le voleur. (The police caught the thief.)
* J'ai attrapé un rhume. (I caught a cold.)
* J'ai attrapé son regard. (I caught his eye.)
* Je n'ai pas compris ce que tu as dit. (I didn't catch what you said.)
So, the best translation depends on the specific situation.