Lewis & Short

2. casnar, acc. to Quint. 1, 5, 8 Gallic, = assectator, attendant (Meyer, l. l. and Or. Rom. Fragm. p. 530 compares the old French, casnard, flatteur, adulateur; casnarder, aduler, idolatrer. But it is to be remarked that the best MSS. of Quint. l. l. give casami, casamo, casamum, and the like; v. Spald. and Zumpt N. cr. ad h. l.).