'Guāi bǎo bǎo' literally combines 乖 (guāi, 'well-behaved, obedient') and 宝宝 (bǎo bǎo, 'baby, darling'), forming an affectionate, gentle term of endearment used primarily for young children — especially when praising or soothing them. It conveys warmth, tenderness, and approval, similar to English phrases like 'good baby' or 'sweetheart' but with stronger nurturing nuance.

The term is commonly used by parents, grandparents, caregivers, or even teachers addressing toddlers or preschoolers. While it can occasionally be used playfully toward adults in very intimate relationships (e.g., between romantic partners), that usage is rare and context-sensitive. The repetition of 宝 emphasizes closeness and cherishing — much like reduplication in other Chinese terms of endearment (e.g., 小小、慢慢). It carries no negative or sarcastic connotation unless heavily intonated in specific ironic contexts, which beginners should avoid.