launch forth (upon something)
to set out on something; to begin on something, such as a journey or a long lecture or sermon. (Upon is formal and less commonly used than on.) We launched forth on our trip before dawn. What time shall we launch forth tomorrow morning?
launch into something
to start in doing something. Now, don't launch into lecturing me about manners again! Tim's mother launched into a sermon about how to behave at the dinner table.
launch (one's lunch)
Sl. to empty one's stomach; to vomit. When I saw that mess, I almost launched my lunch. Watch out! She's going to launch!
launch out on something
to start out to do something or go somewhere. When are you going to launch out on your expedition? Ted and Bill launched out on their trip through the mountains.
launch something against someone or something
to set something going against someone or something. The general launched an attack against the town. Claire launched a gossip attack against James.
set forth on something
and launch forth on something 1. Lit. to start out on something, such as a journey. We intend to set forth on our journey very early in the morning. What time will you launch forth on your trip?
2. Fig. to begin presenting a speech or an explanation. As soon as John set forth on his speech, three people walked out. Every time he launches forth on a presentation, it's a half hour before he shuts up.