WordPress at a glance
action is not described

rest_insert_(taxonomy) action-hook . WP 4.7.0

Fires after a single term is created or updated via the REST API.

The dynamic portion of the hook name, $this->taxonomy, refers to the taxonomy slug.

Usage

add_action( 'rest_insert_(taxonomy)', 'action_function_name_9403', 10, 3 );
function action_function_name_9403( $term, $request, $creating ){
	// action...
}
$term(WP_Term)
Inserted or updated term object.
$request(WP_REST_Request)
Request object.
$creating(true/false)
True when creating a term, false when updating.

Where the hook is called

WP_REST_Terms_Controller::create_item()
WP_REST_Terms_Controller::update_item()
wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php 440
do_action( "rest_insert_{$this->taxonomy}", $term, $request, true );
wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php 542
do_action( "rest_insert_{$this->taxonomy}", $term, $request, false );

Where the hook is used (in WP core)

Does not used.