Adjective
throttleable (not comparable)
Capable of being throttled.
a throttleable engine
In a throttleable ducted rocket, also known as a variable flow ducted rocket, a valve allows the gas generator exhaust to be throttled allowing control of the thrust. Source: Internet
Like liquid rocket engines, hybrid rocket motors can be shut down easily and the thrust is throttleable. Source: Internet
The engines had 18 nozzles to disperse the exhaust and minimize effects on the ground, and were throttleable from convert. Source: Internet