The nurse calls Juliet a lamb and a ladybird, then she catches herself, exclaming, “God forbid!” Her exclamation can be read in two ways: as an expression of fear that Juliet’s late arrival indicates something has gone wrong, or an expression of  embarrassment that in using the term “ladybird” she has inadvertently referred to Juliet with a sexually derogatory term in front of her parents. In Shakespeare's day, “ladybird” was slang for a promiscuous woman or sex worker.