Definitions

1. adjective

most unclean or impure; having the greatest amount of dirt or filth

“The smuttiest part of the old factory was where the machinery had been neglected for years.”

2. superlative comparative

used to compare two things and indicate which one is the most unclean or impure

“Of all the beaches we visited, this one is the smuttiest.”

3. noun

the state or quality of being unclean or impure

“The smuttiest part of the city was where the pollution was worst.”