Correct spelling for the English word "slowth" is [slˈə͡ʊθ], [slˈəʊθ], [s_l_ˈəʊ_θ] (IPA phonetic alphabet).
The word "slowth" is derived from the Middle English word "slouthe" which meant "slowness" or "slothfulness". It can be traced back even further to the Old English word "slǽwð" with the same meaning. The Old English word "slǽwð" is a combination of "slǽw", meaning "slow", and the suffix "-ð", denoting a state or condition. Over time, "slouthe" evolved into "slowth" while retaining its original meaning of sluggishness or laziness.