^start of string
Negative Lookahead(?!.*(?:o)) .*any character (except for line terminators), repeated any number of times
othe literal o (11110 / 1578 / 6F16) (case insensitive)
A-zone character from A (6510) to z (12210) (case insensitive)
\da digit
\da digit
wthe literal w (11910 / 1678 / 7716) (case insensitive)
\sany whitespace character
\w{4}any word character, repeated exactly 4 times
$end of string, or before its final line terminator
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters