Separate kanji for おそい when referring to being late and being slow

Question

The i-adjective はやい can refer to being fast or being early, but each of the meanings has affinity towards separate kanji: 速い (fast) and 早い (early). Yet, while it's not surprising that the antonyms of both 速い and 早い have the same pronunciation おそい, both おそい that means "slow" and "late" seems to share the same kanji: 遅い. Although WWWJDIC and dictionary@goo both include 鈍い as an alternative kanji for おそい, it does not seem to have affinity towards any of the two meanings either.

Is this really the case that the same kanji form can refer to both meanings, or were there separate kanji for each (maybe abolished during the reform or something)?

Answer 1

大辞泉 shows 鈍い as well, but I think this is more often 【のろい】. However, the same dictionary shows that (this) のろい can also mean "slow of speed"; but I've heard it mostly used as "slow-witted".

As an aside, 鈍い can be any of 【のろい】, 【にぶい】, or 【おそい】. They all carry different primary meanings though, so be careful of their usage.

Is this really the case that the same kanji form can refer to both meanings, or were there separate kanji for each (maybe abolished during the reform or something)?

Yes, I don't see why not. 高い is the same type, meaning "high" or "expensive". And its opposites are very different (低い and 安い, resp.)