filter - Regex filtering list of words -

I need a simple regex, but I can not do it by my own I have no luck with different methods I try to do

I have a list of words for which I have to separate from my lessons.

  text = hoy es un dia soleado y ma ±   
 list of words that I will filter by text:  y  ,  es ,  s ,  es ,  un ,  UN ,  un ,  Las ,  Los ,  la ,  lo , etc  
 then The resultant text will be:  <<< Code>      
 These words will be a filter list that I need to filter with my texts is.  
 I tried to do something like this:  
  (?! [LL] [AAO] [SS] * \ b [[EE]? [LL] \ b ]) [\ W] +   
 so I can filter with:  
  ?! [LL] [AAO] [SS] * \ b  word  las ,  loss ,  las ,  ,  lo   
  [EE]? [Ll] \ b]  the word  l ,  l   EL ,  eL   < P> But if I apply, then the letter L and L are not filtered.  
 How can I do this regex?   
 
 
  s / \ b (y | es | es | un | UN | combined Explanation:  
  \ b  is a word boundary. It looks for places where words break, but in reality nobody chooses.