1. in a manner that lacks something necessary or required; inadequately or insufficiently
Usage: formal; often used in technical or academic contexts

Examples

• The student performed deficiently on the exam because she had not studied the material.
• The heating system was working deficiently during the cold winter months.
• The team played deficiently in the first half, missing several easy opportunities.
• Nutrients were being absorbed deficiently due to the digestive disorder.
• The software was functioning deficiently, causing frequent crashes and errors.