python regex exclude text containing word

Something like this?

 # ^(?s)((?!X).)*W((?!Y).)*$

 ^ 
 (?s)
 (
      (?! X )
      . 
 )*
 W 
 (
      (?! Y )
      . 
 )*
 $

or, with word boundries

 # ^(?s)((?!\bX\b).)*\bW\b((?!\bY\b).)*$

 ^ 
 (?s)
 (
      (?! \b X \b )
      . 
 )*
 \b W \b 
 (
      (?! \b Y \b )
      . 
 )*
 $

edit - It was unclear if you meant X<->W<->Y was separated by whitespace
or any number of characters. This expanded, commented example shows both ways.
Good luck!
Note - the (?add-remove) construct is a modifier group. Typically its a way to
embed options like s (Dot-All), i(Ignore case), etc.., within the regex.
Where (?s) means add Dot-All modifier, and (?si) is the same but with ignore case as well.

 #  ^(?s)(?!.*(?:\bX\b\s+\bW\b|\bW\b\s+\bY\b))(?:.*\b(W)\b.*|.*)$

 # This regex validates W is not preceded by X
 # nor followed by Y.
 # It also optionally finds W.
 # Only fails if its invalid.
 # If passed, can check if W present by
 # examining capture group 1.

 ^                         # Beginning of string
 (?s)                      # Modifier group, with s = DOT_ALL
 (?!                       # Negative looahead assertion
      .*                        # 0 or more any character (dot-all is set, so we match newlines too)
      (?:
           \b X \b \s+ \b W \b       # Trying to match X, 1 or more whitespaces, then W
        |  \b W \b \s+ \b Y \b       # Or, Trying to match W, 1 or more whitespaces, then Y

           # Substitute this to find any interval between X<->W<->Y
           #    \b X \b .* \b W \b       <- Trying to match X, 0 or more any char, then W
           # |  \b W \b .* \b Y \b       <- Or, Trying to match W, 0 or more any char, then Y
      )
 )

 # Still at start of line. 
 # If here, we didn't find any X<->W, nor W<->Y.
 # Opotioinally finds W in group 1.
 (?:
      .* \b 
      ( W )                     # (1), W
      \b .* 
   |  
      .* 
 )
 $                         # End of string