The Collaborative International Dictionary of English v.0.48:

Unreined \Unreined\
   See reined.

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "unreined":
   abandoned, disobedient, go-go, headstrong, heady, immoderate,
   incontinent, indulgent, insubordinate, intemperate, irrepressible,
   irresponsible, lawless, lax, licentious, loose, mutinous,
   nonrestrictive, out of control, out of hand, permissive, rampant,
   reinless, riotous, self-willed, unaccountable, unbridled,
   unchecked, uncoerced, uncompelled, unconstrained, uncontrolled,
   uncurbed, undisciplined, unforced, ungoverned, uninhibited,
   unmastered, unmeasured, unmuzzled, unrepressed, unreserved,
   unrestrained, unrestrictive, unruly, unsubdued, unsuppressed,
   wanton, wild, wildcat, willful