The Collaborative International Dictionary of English v.0.48:

Interjectional \In`ter*jec"tion*al\, a.
   1. Thrown in between other words or phrases; parenthetical;
      ejaculatory; as, an interjectional remark.
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   2. Pertaining to, or having the nature of, an interjection;
      consisting of natural and spontaneous exclamations.
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            Certain of the natural accompaniments of
            interjectional speech, such as gestures, grimaces,
            and gesticulations, are restrained by civilization.
                                                  --Earle.
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