Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "ceást-full." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 149.
contentious, quarrelsome :-- Ne beó ðú tó ceástful; of irsunge wyxt seófung, Prov. K. 23. Gálful þing wín, and ceástfull (tumultuosa) druncennyss, Scint. 105, 5.