Lewis & Short

compendĭo, āvi, ātum, 1, v. a. [compendium] (eccl. Lat.).

  1. I. To shorten, abridge: sermonem, Tert. adv. Marc. 4, 9; 4, 1.
  2. II. Compendiare alicui, lit., to shorten the way of life for one; hence, to kill him, Aug. Quaest. in Hept. 7 fin.