Wiktionary
uncontainable
a. of something which cannot be contained
Usage examples of "uncontainable".
For anyone who has witnessed a portentous scientific finding in the making - the July 1994 impact of Comet Shoemaker-Levy 9 with Jupiter comes to mind - it will be clear that scientists tend to be effervescent and uncontainable.
A flush of heat, raw and uncontainable, his blood transformed to dry prairie grass that some fool had set alight, the conflagration racing up his arms like a runaway wildfire, consuming him from fingers to toes in a single heartbeat.