1. in a way that does not follow a regular pattern or schedule
2. in a way that does not conform to rules or normal standards

Examples

• The bus arrives irregularly, so it's hard to plan your schedule.
• She attended meetings irregularly throughout the year.
• The medication was taken irregularly, which reduced its effectiveness.
• His heartbeat was beating irregularly after the exercise.
• The students were seated irregularly around the classroom.
• The company operated irregularly without proper permits.