I don't want match abc with spaces AT ALL if followed by some other non space characters

I use this regex https://regex101.com/r/7Cw1fy/1

abc(\s*)(?![\S]+)

abc matches -> OK

abc cde matches -> not OK

>Solution :

You can use

abc(?!\s*\S)(\s*)

See the regex demo. Details:

• abc – a fixed string
• (?!\s*\S) – a negative lookahead that fails the match if there are zero or more whitespaces followed with a whitespace immediately to the right of the current location
• (\s*) – Group 1: zero or more whitespaces.