using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var mainList = new List<string>() { "looking_for_specific_word", "has_specific_word", "doesnt_have_word" };

            var reservedList = new List<string>() { "specific", "Bob", "Loblaws" };

​

​

            var result = mainList.Where(x => reservedList.Any(z =>x.Contains(z)));

​

            foreach (var item in result)

            {

                Console.WriteLine(item);

            }

    }

}