Source : Webster's Revised Unabridged Dictionary (1913)

Inopportune \In*op`por*tune"\, a. [L. inopportunus: cf. F.
   inopportun. See {In-} not, and {Opportune}.]
   Not opportune; inconvenient; unseasonable; as, an inopportune
   occurrence, remark, etc.

         No visit could have been more inopportune. --T. Hook.

Source : WordNet®

inopportune
     adj : not opportune; "arrived at a most inopportune hour"; "an
           inopportune visit" [ant: {opportune}]