quasi-retarded

A hindered less efficient functionality.

The electrician installed the light switch incorrectly. Although the light still turned on, the switch didn't fully click in the upright position so therefore is quasi-retarded.

The throttle cable on the old ford doesn't fully retract causing the engine to idle at a higher RPM. It's quasi-retarded.

The billing system is quasi-retarded. It accepts debit cards initially, but not after you try a new debit card. Customer service insists they don't accept debit cards.