In a manner that is suitable for or capable of being covenanted; in accordance with the terms of a covenant.
From covenable plus the adverbial suffix -ly, maintaining the covenant root meaning of binding agreement or mutual promise.
This rare adverb exists almost entirely in historical legal documents, where precision about whether something could 'covenably' be done was the difference between a valid contract and a worthless one.
Complete word intelligence in one call. Free tier — 50 lookups/day.