Thrust to mass ratio
Thrust-to-weight ratio is a dimensionless ratio of thrust to weight of a rocket, jet engine, propeller engine, or a vehicle propelled by such an engine that indicates the performance of the engine or vehicle. [Wikipedia: https://en.wikipedia.org/wiki/Thrust-to-weight_ratio]
Mechanics
QUDT
http://qudt.org/vocab/quantity#ThrustToMassRatio
Same dimensionality as linear accelleration
ODM2 Units Type Controlled Vocabulary
ODM2 Working Group
A vocabulary for describing the type of the Unit or the more general quantity that the Unit represents.