1. connect or meet someone, have a meeting, do something you should have done earlier
catch up with/on gossip/TV shows/emails/a friend
The phrasal verb 'hook up' can mean a connection or link. You can 'hook up to the grid' for electricity or 'hook up to electricity'. Hook up can also refer to a meeting of people to communicate or cooperate. In a casual colloquial context, to 'hook up' with someone can mean to have a sexual encounter with someone, so be careful about the context you use this phrasal verb in.
The phrasal verb 'catch up' means to arrive at the same place as someone ahead of you or to complete tasks which have been accumulating. As a noun, a 'catch up' is a meeting between people where they discuss developments or changes from the last time they met.