In Colombia it means small, often, little value, something that lacks value, thing of very little value. It is synonymous with baladí, bicoca, borrufalla , bauble, fruslería , furrufalla, insignificant.
First of all, we should know that it is a strange case of enantiosemia, because it is not given by antiphrasis or irony but by confusion of adverbs. In Spanish it means "a lot, in large quantity" and comes from the neutral adverb Latin nimium ( "excessive, large, exaggerated" ) ; but at some point it was mistaken for a version of minimum ( "small") and was also used as "little, minimal" that ended up becoming a more popular concept than the original, so today both coexist in the English dictionary.
mediocre