In a couth or refined manner; sophisticatedly and politely.
Formed from 'couth' with the adverb suffix '-ly,' though rarely used since 'couth' itself is somewhat facetious and informal.
Couthly exists as a word but almost nobody uses it—it's like you can feel the humor built into it, making people instinctively avoid it in serious contexts.
Complete word intelligence in one call. Free tier — 50 lookups/day.