caco- Look up caco- at
before vowels cac-, word-forming element meaning "bad, ill, poor" (as in cacography, the opposite of calligraphy), from Latinized form of Greek kako-, from kakos "bad, evil," considered by etymologists probably to be connected with PIE *kakka- "to defecate" (see caca). The ancient Greek prefix was common in compounds; when added to words already bad, it made them worse; when added to words signifying something good, it implies too little of it.