1. existing or happening in some places but not others; uneven or irregular
2. of poor or variable quality; incomplete

Examples

• The fog was patchy, clearing in some areas but thick in others.
• Her knowledge of history is rather patchy.
• The grass grew in patchy areas across the lawn.
• Internet service in rural areas can be patchy.
• The paint job looked patchy where it had worn thin.
• His attendance at school has been patchy this semester.
• The team’s performance this season has been patchy at best.