In Portuguese we have a word sonso* plus a slang expression João-sem-braço ("John-missing-an-arm" or more poetically "Joe-missing-an-arm" — don't ask me why) to define a person who is doing something illegal or immoral but is pretending not to be aware of that fact. Someone feigning innocence.
For example, there is a huge line to buy tickets or something. The person arrives at some point in the line and starts talking to someone at random and continues to be nearby, with the intention of cutting the line in a smooth way, without other people noticing.
Is there a word, a phrase, or some idiomatic expression (even if informal slang) to define that kind of person?
* Definition of sonso from the Dicionário Priberam:
adjectivo e substantivo masculino
- Que ou quem finge ser o que não é. = DISSIMULADO, FINGIDO
- Que ou quem faz coisas reprováveis ou desonestas às escondidas.
- Que ou quem tem ares e aparência de ingénuo. = FINÓRIO, MANHOSO, VELHACO
Pronounced /ˈsõsu/ and meaning roughly:
- Something or someone that pretends to be or which isn’t. = DISSEMBLING, FEIGNED
- Something or someone that does reprehensible or dishonest things in secret.
- Something or someone that has the air or appearance of an innocent. = SLY, CUNNING, TREACHEROUS/RASCAL