A sudden period of uncontrolled anger like a young child’s. (Cambridge Dictionary)
A fit of bad temper. (Merriam – Webster)
An uncontrolled outburst of anger and frustration, typically in a young child. (Oxford Dictionaries)
If a child has a tantrum, they lose their temper in a noisy and uncontrolled way. If you say that an adult is throwing a tantrum, you are criticising them for losing their temper and acting in a childish way. (Collins Dictionary)
14 Ways to Tame Your Kid’s Tantrums.
Tantrums: why they happen and how to respond.