To "call a spade a spade" is a figure of speech which explicitly calls out something as it is, by its right name. The implication is not to lie about what something is and instead to speak honestly and directly about a topic, specifically topics that others may avoid speaking about due to their sensitivity or the unpleasant or embarrassing nature of the subject.[1]
Brewer's Dictionary of Phrase and Fable (1913) defines it as: