sit in

Từ điển WordNet v3.1 - WordNet Dictionary

verb

1. attend as a visitor
- Can I sit in on your Intermediate Hittite class?
• Hypernyms:
attend, go to
• Verb Frames:
- Somebody ----s PP
2. participate in an act of civil disobedience
• Derivationally related forms:
sit-in
• Hypernyms:
disobey
• Verb Frames:
- Somebody ----s