The idioms are back again, hurray! Today’s instalment is all about the naughty side of tomfoolery. That’s right, although the phrase ‘to pull someone’s leg’ now denotes a friendly bit of banter, meaning something like ‘to make fun of somebody by making them look foolish’, it actually used to have criminal undertones.
There are many proposed origins for the phrase, but my research suggests that pulling someone’s leg was originally a method used by thieves to entrap their quarry and thereby relieve them of their valuables. One thief would be assigned ‘tripper up’ duty, and would use various instruments (usually a wire) to knock the target to the ground. Whilst the hapless victim crawled about on the floor, the other members of the gang would rush in to complete the robbery.
It is not difficult to see how the comical effect of somebody being tripped over during the course of bit of skulduggery might have given rise to today’s meaning of the phrase.
I am not American (praise Jebus) but I gather that ‘pulling someone’s leg’ in American English retains a sinister edge, alluding to an element of trickery or deception in the part of the leg puller. Perhaps this might be a lingering connotation from the idiom’s less than Christian origin.