Regex matching multiple negative lookahead

Lookahead (?=foo), (?!foo) and lookbehind (?<=foo), (?<!foo) do not consume any characters.

You can do multiple assertions:

^(?!abc:)(?!defg:)

or:

^(?!defg:)(?!abc:)

...and the order does not make a difference.

Try doing this :

^(?!(?:abc|defg):)