hardworking, more hardworking, most hardworking hardworking, less hardworking, least hardworking You can also breakup hardworking into its constituent words "hard" and "working". You will then also have: hard working, harder working and hardest working

Hardworking does not inflect; that is, you can only say 'more hardworking' or 'most hardworking'.

Comparative: Jack is more Hardworking than John. (Compare to things) Superlative: Jack is the Hardest Working person we have. (Implies level of quality)

Thank you all for such fast answers!