Idiom of the day :- A slippery customer

Usage, examples and definition of the Idiom :-

Does Mr. Jansen look like a slippery customer as he stands in the doorway of his business establishment ? If you knew that ‘slippery’ is a colloquialism meaningcunning and untrustworthy, and ‘customer’ means a person, I think you’d say yes. ‘Be very careful of Mr. Jansen. He has a reputation of being a slippery customer.