If "lecture" means a formal talk:
* Conversation: A casual, informal exchange of ideas.
* Discussion: A collaborative exchange of ideas, opinions, or information.
* Dialogue: A conversation between two or more people.
* Informal talk: A casual, non-formal presentation.
If "lecture" means a reprimand:
* Praise: Expressing approval or admiration.
* Encourage: To give support and confidence to someone.
* Compliment: An expression of admiration or approval.
If "lecture" means to teach in a formal setting:
* Learn by doing: Gaining knowledge through practical experience.
* Self-learning: Acquiring knowledge independently through research, reading, or other methods.
Other potential antonyms:
* Play: Engaging in enjoyable activities.
* Relax: To rest and unwind.
* Entertain: To provide amusement or enjoyment.
The best antonym for "lecture" will depend on the specific context in which it's used.