Lewis & Short

2. offensus, ūs, m. [1. offendo], a striking against, a shock (poet. and in post-class. prose).

  1. I. Lit., Lucr. 2, 223; 4, 359; Tert. adv. Marc. 4, 39.
  2. II. Transf.
        1. a. A lighting upon, meeting with: per offensus armorum, Stat. Th. 12, 283.
        2. b. An offence, vexation, annoyance: sin vita in offensu est, Lucr. 3, 941.