Regular Expressions 101

\ban ASCII word boundary

Negative Lookahead(?!\w*(\w)(\w)\2\1)

\w*any word character, repeated any number of times

Group 1(\w)

\wany word character

Group 2(\w)

\wany word character

\2the text saved by group 2

\1the text saved by group 1

\w+any word character, repeated at least once

\ban ASCII word boundary

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

\b(?!\w*(\w)(\w)\2\1)\w+\b

New

Words that it must exclude:
abba // (ab/ba pair)
smelled // (el/le pair)
trillion // (il/li pair)
test

Words that it must exclude:
abba // (ab/ba pair)
smelled // (el/le pair)
trillion // (il/li pair)
test