What does the expression “not a kick in the teeth” mean?
Someone has no idea about the subject they are talking about — they just “ни в зуб ногой” (“ni v zub nogoi” or “not even a kick in the teeth”) about it!
This expression appeared in the Russian language in the 19th century and, roughly translated, sounded like “they don’t know a kick in the teeth [about something]”. Grammatically speaking, the person in question wouldn’t even be able to kick someone in the teeth, if push comes to shove (weird, we know!). Over time, only the expression was shortened to only the first part. And the meaning changed to figurative — they began to say this about a person who doesn’t know anything, or can’t do anything.
So if a person tells you that they don't know a kick in the teeth about something, don’t be confused - the expression has nothing to do with acrobatics.
An English equivalent of this idiom is “Doesn’t know beans about something”.
