/ ˌʌnˈkliːn; NAmE / adjective
1.
( formal ) dirty and therefore likely to cause disease :
unclean water
OPP clean
2.
considered to be bad, immoral or not pure in a religious way, and therefore not to be touched, eaten, etc.
SYN impure :
unclean thoughts
unclean food
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WORD ORIGIN
Old English unclǣne (see un- , clean ).