Sure it's possible! It's a matter of grouping:
a((?!cold).)+?night
works, because the outer parentheses group is what gets repeated, and inside the parentheses every single character is checked to not have 'cold' in front of it.
For added fun, you can add word boundaries before and after 'cold', so it will not reject 'a scolding hot night' 
a((?!cold).)+?night
(Ed.: Added '?' after the pluses so it will match shortest possible strings only — usually, that's what you'd want.)
This article was last modified on July 21, 2010
This article was first published on
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