The Collaborative International Dictionary of English v.0.48:

Concision \Con*ci"sion\, n. [L. concisio: cf. F. concision. See
   Concise.]
   A cutting off; a division; a schism; a faction. --South.
   [1913 Webster]

WordNet (r) 3.0 (2006):

concision
    n 1: terseness and economy in writing and speaking achieved by
         expressing a great deal in just a few words [syn:
         conciseness, concision, pithiness, succinctness]

Easton's 1897 Bible Dictionary:

Concision
   (Gr. katatome; i.e., "mutilation"), a term used by Paul
   contemptuously of those who were zealots for circumcision (Phil.
   3:2). Instead of the warning, "Beware of the circumcision"
   (peritome) i.e., of the party who pressed on Gentile converts
   the necessity of still observing that ordinance, he says,
   "Beware of the concision;" as much as to say, "This circumcision
   which they vaunt of is in Christ only as the gashings and
   mutilations of idolatrous heathen."