adj. dirt·i·er, dirt·i·est
a. Covered or marked with dirt or an unwanted substance; unclean.
b. Spreading dirt; polluting: The air near the foundry was always dirty.
c. Apt to soil with dirt or grime: a dirty job at the garage.
d. Contaminated with bacteria or other infectious microorganisms.
2. Squalid or filthy; run-down: dirty slums.
a. Obscene or indecent: dirty movies; a dirty joke.
b. Lewd or lecherous: a dirty mind.
a. Unethical or corrupt; sordid: dirty politics.
b. Malicious or scandalous: a dirty lie.
c. Not sportsmanlike: dirty players; a dirty fighter.
d. Acquired by illicit or improper means: dirty money.
e. Slang Possessing or using illegal drugs.
a. Unpleasant or distasteful; thankless: Laying off workers is the dirty part of this job.
b. Extremely unfortunate or regrettable: a dirty shame.
6. Expressing disapproval or hostility: gave us a dirty look.
7. Not bright and clear in color; somewhat dull or drab. Often used in combination: dirty-blonde hair; dirty-green walls.
a. Relating to or being a bomb that uses a conventional explosive and radioactive material to contaminate an area with low-level radiation.
b. Relating to or being a nuclear weapon that produces a very great amount of long-lived radioactive fallout.
9. Stormy; rough: dirty weather.
v. dirt·ied, dirt·y·ing, dirt·ies
1. To make soiled.
2. To stain or tarnish with dishonor.
To become soiled.
Synonyms: dirty, filthy, grimy, grubby, squalid
These adjectives apply to what is unclean, impure, or unkempt: dirty clothes; filthy rags; grimy hands; an old grubby stove; a squalid apartment.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.