Noun: 1. A term used for undergarments worn for an entire business day that will more than likely need to be peeled off by the wearer as soon as he or she gets home.
2. Undergarments that must be taken off immediately one is able to do so in order to feel comfortable--usually giving off faint odor.
**In most cases, grendels have been worn longer than 12 hours or are crafted from unbreathable fabrics. The worst grendels are the ones worn underneath panty hose for 8+ hours.
After a long day of teaching tennis, Mark had to peel off his sweaty grendels and hop directly into the shower before doing anything else.