Regex.Match whole words

In C#, I want to use a regular expression to match any of these words:

string keywords = "(shoes|shirt|pants)";

I want to find the whole words in the content string. I thought this regex would do that:

if (Regex.Match(content, keywords +"\\s+",   RegexOptions.Singleline | RegexOptions.IgnoreCase).Success){    //matched}

but it returns true for words like participants, even though I only want the whole word pants.

How do I match only those literal words?