When you 'put your foot in your mouth', you say something tactless or embarrassing, usually at an unfortunate moment. This idiom expresses a form of regret and acceptance of blame, as it is usually the result of an accident or error of judgement rather than a deliberate act. Despite that, the result is often somebody being offended or upset. That can not only be embarrassing for you; it can also get you into trouble, particularly if the person you offended is someone in authority, like your boss. The expression can be used in a social and professional context, but is more common as a social blunder. In the UK, you are more likely to encounter the variation 'put your foot in it'. Phrases with a similar meaning include 'commit a faux pas', and 'shoot yourself in the foot'.