"tough" is a very common term, has very clear meaning, has all main TLDs already taken, is a short name, very easily passes the radio test, is extremely memorable, is very specific, is catchy, is very easy to pronounce, has high overture, has great business applicability, is very relevant for recreational activities, with perfect lifestyle capabilities, is a natural scientific fit, is a tremendous choice as a shopping domain, and it is perfect in the technology space.