In a manner that is somewhat bad or somewhat poorly; to a degree that is noticeable but not severe.
From 'baddish' with the standard adverbial suffix '-ly,' creating an adverb modifier. Following the productive English pattern of adjective-to-adverb conversion through '-ly' addition.
English adverbs ending in '-ly' are so common we forget how peculiar it is that we add 'ly' (from Old English 'lic' meaning 'body' or 'like') to transform how we modify actions—'bad' becomes 'baddishly,' literally meaning 'in a bad-like manner.'
Complete word intelligence in one call. Free tier — 50 lookups/day.