Depending on the regex flavor, you can probably use a negative lookahead. Like this:
word(?! (something))
Just checks to make sure there isn't a space and the word something after the matched word.
Oh, and if you have JUST the word "word" in the string, you could do:
^word$
which makes sure that word
is the start (^)
and the end ($)
of the string.
But if you had JUST the word "word" in the string, you could have just done
wordString == "word"; // or wordVariable in place of "word", or whatever
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…