The phrase "bookable offence" means an action or behavior that is against the rules and can be recorded by an official (or "booked") as a violation. Full definition
The Royals looked like they had come for a point by sitting very deep with very little attacking threat but when David Edwards was sent off for a second bookable offence for what looked a mindless foul it was just a matter of time for the home side. (avillafan.com)
The Arsenal right - back could potentially have given away a free - kick and seen himself sent off for a second bookable offence for this challenge on Young just minutes after the Gunners took the lead. (caughtoffside.com)
So I for one was surprised that Mister Dean did not bottle the decision to send off Juan Mata for a second bookable offence in the game between Manchester United and West Brom at the Hawthorns. (justarsenal.com)