to attempt to master a difficult videogame/puzzle/craft to perfection in a matter of days by sitting on your ass for hours on end as if (or because) you have no life.

It’s an acronym standing for Can’t Remember A Fucking Thing. It’s usually used to describe embarrassment at being unable to remember someone (CRAFT moment); going onstage as the lead in the latest theatrical performance and your mind goes completely blank (CRAFT situation); the next morning after a night when you got pissed as a fart and woke up in bed cuddling a traffic cone and a string of fairy lights wound round your prick.

To do months of work within days, reject social invitations, and only leave the house to buy take-away because you must work hard to do well. Synonymous with IT certifications or playing computer games.

To sit at home and play video/computer games all day.

To nolife is to commit tons of hours to a goal. Typically seen in gaming but can apply to anything.