In a cumbersome or unwieldy manner; in a way that is heavy and difficult to manage.
From the adjective 'cumbrous' with the adverb-forming suffix -ly added. Follows the standard English pattern of converting adjectives to adverbs.
The -ly suffix is one of English's most productive word-building tools—it takes any adjective and turns it into an adverb, which is why we can create words like 'cumbrously' even if they're rarely used.
Complete word intelligence in one call. Free tier — 50 lookups/day.