What slang expressions in your language cannot be found in any dictionary, but are actually used by locals?

I remembered the words I used as a child, but over time it disappeared like ancient dead languages. These are "Дяпчик" and "Тёханша", which means man and woman. Apparently "Дяпчик" actually really means something like "little man", but "Тёханша" is really a non-existent rare word