On the back/front foot

To be on the back foot can mean to hang back, to be on the defensive, or to be unprepared, while to be on the front foot means the opposite. When the word ‘caught’ is added, the level of defence or unpreparedness is more definite. The figurative meaning of these phrases date from the turn of the 19th/20th century and they may have their origin in sport, but it is not certain from which sport. Some sources maintain the source is cricket, others maintain the source is boxing and even fencing has been put forward as a candidate. In cricket, one is not necessarily on the defensive when on the back foot, and the same can be said for boxing or fencing when it can be a ploy or a feint before launching an attack. Because the exact sporting context remains obscure and debatable, the expression may not derive from sport at all. To be on the back foot could simply mean to hang back, the opposite in fact of putting one's best foot forward, which means to get on with something in a positive manner, and dates from the late 16th century.