småningom

Etymology
First attested in 1587, an adverb with the looks of a dative plural (-om ending), based on, possibly based on Old Swedish adverb smam (dative plural of små) after the m shifted into an n; same as 🇨🇬.

The separation into småning om is very rare, and probably unhistoric. This is not the preposition, but a dative ending.

Adverb

 * 1) after some time; sooner or later, eventually