A "psycho" is someone who is acting wildly crazy or insane ("Stop waving around that knife, you psycho!") A "sicko" is someone who is "sick" in the head, who says or does something perverse or gross or really disturbing... (Nastya: "thx" is just an abbreviated form of "thanks", used in texts and allll over the interwebs... :) )

Both are slang. What is the difference between"thx" and "thanks"?