1
general::
Phrase(s): spring (up)on someone, something, or an animal
to jump on someone, something, or an animal; to pounce on someone, something, or an animal. (Upon is formal and less commonly used than on.) • The lion sprang upon him and knocked him down. • The cat sprang on the mouse and captured it., Phrase(s): spring something on someone
1. to surprise someone with something. • I hate to spring this on you at the last moment, but I will need some money to travel on. • Please don’t spring any other demands on me. 2. to pull a trick on someone. • Let me tell you about the trick I sprang on Sally. • What are you going to spring on her this time?
McGrawhill's American Idioms And Phrasal Verbs