using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

       public class ObjectA

   {

      public List<string> StringList { get; set; }

   }

​

    public static void Main()

    {

         List<ObjectA> myObjectList = new List<ObjectA>()

                                         {

                                            new ObjectA()

                                               {

                                                  StringList = new List<string>()

                                                                  {

                                                                     "asd",

                                                                     "asdfg"

                                                                  }

                                               },

                                            new ObjectA()

                                               {

                                                  StringList = new List<string>()

                                                                  {

                                                                     "asd4565",

                                                                     "asdfg"

                                                                  }

                                               }

                                         };

         List<string> wordsToFind = new List<string>{"asd","sdf"};

​

         var results = myObjectList.Where(x => x.StringList.All(y => wordsToFind.Any(z => y.IndexOf(z) >= 0)));

        foreach(var result in results)

        {

            Console.WriteLine(string.Join(",", result.StringList));

        }

    }

}