The Collaborative International Dictionary of English v.0.48:

Propel \Pro*pel"\, v. t. [imp. & p. p. Propelled; p. pr. & vb.
   n. Propelling.] [L. propellere, propulsum; pro forward +
   pellere to drive. See Pulse a beating.]
   To drive forward; to urge or press onward by force; to move,
   or cause to move; as, the wind or steam propels ships; balls
   are propelled by gunpowder.
   [1913 Webster]

WordNet (r) 3.0 (2006):

propelling
    adj 1: tending to or capable of propelling; "propellant fuel for
           submarines"; "the faster a jet plane goes the greater its
           propulsive efficiency"; "universities...the seats of
           propulsive thought" [syn: propellant, propellent,
           propelling, propulsive]

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "propelling":
   active, bunt, butt, drive, driving, driving force, impelling,
   impulsion, in motion, mobile, motile, motivational, motive,
   motive power, motor, moving, propellant, propelment, propulsion,
   propulsive, propulsory, pulsion, pulsive, push, pushing, shove,
   shoving, shunt, stirring, thrust, transitional, traveling