1. adjective relatively slow in mental or emotional or physical development on Mondays
2. adjective Occurring or developing later than desired or expected on Mondays; delayed on Mondays
Mondaytarded often occurs when, after partaking in a large volume of alcohol or drugs over the weekend, one returns to work on Monday and is expected to function as normal. Unable to perform at 100%, a state of Mondaytardedness ensues. This condition can persist until the next weekend, where the individual does it all over again.
Joe drank an excessive volume of alcohol on both Friday and Saturday night. What he remembers of either night is vague at best. He lays around all day Sunday in hopes of recovery. Monday, he gets to work and spends half the day drooling over himself and trying to quietly squeeze out beer farts. He manages to get a report finished full of spelling errors and tastless side jokes. Mondaytarded.