In Colombia and especially in the Coffee Axis it is a word used by the muleteers. It means brake, head, jáquima for beasts.
It is a free rein loose/does not have free rein / with no should rienda worth... ( is indomito, indomitable, ungovernable ).Book " THE language of the Argentine expressions, perceptions, and idioms that link us "
In Argentina we say " which handles the lead " so as " the kitchen or stir stew ".Recommend you consult the book "The language of the Argentines, expreciones, perceptions and idioms that link us " It is the first of its kind.