The Collaborative International Dictionary of English v.0.48:

Obstructive \Ob*struct"ive\, a. [Cf. F. obstrictif.]
   Tending to obstruct; presenting obstacles; hindering; causing
   impediment. -- Ob*struct"ive*ly, adv.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Obstructive \Ob*struct"ive\, n.
   An obstructive person or thing.
   [1913 Webster]

WordNet (r) 3.0 (2006):

obstructive
    adj 1: preventing movement; "the clogging crowds of revelers
           overflowing into the street" [syn: clogging,
           hindering, impeding, obstructive]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "obstructive":
   choking, complaining, constrictive, contrary, counterproductive,
   crosswise, disputatious, disputing, dissentient, dissenting,
   fractious, hindering, hindersome, in the way, inhibiting,
   inhibitive, interrupting, interruptive, noncooperative, objecting,
   obstructing, obstruent, occlusive, on the barricades,
   proof against, protesting, rebellious, recalcitrant, refractory,
   reluctant, renitent, repellent, repressive, resistant, resisting,
   resistive, restrictive, retardant, retardative, stifling,
   strangling, suppressive, troublesome, uncooperative, unsubmissive,
   unyielding, up in arms, withstanding