Mudguards guard you from mud (true), and it's not unfair to assume they also guard you from other things, much less common than mud, but also in the "crap on the floor" category, e.g. oil, snow, water, poo.
Fenders... fend. Fend what? Fend off paedophiles? A fender a day keeps the doctor away?
You can turn that on its head:
Mudguards guard you from mud (true), and it's not unfair to assume they also guard you from other things, much less common than mud, but also in the "crap on the floor" category, e.g. oil, snow, water, poo.
Fenders... fend. Fend what? Fend off paedophiles? A fender a day keeps the doctor away?