The opening left-falling 丿 sweep is the indexing Kangxi radical for 乎. It groups it with other cursive piě-radical particles (乃, 之, 乏) where a single sweeping diagonal at the start of a fused glyph serves as the lookup anchor.
pictograph
乎hū
exhaled breath; question particle
The remainder pictures breath rising in puffs above a base — the original meaning was 'breath escaping upward'. This image of exhalation gave 乎 its function as a classical question or exclamation particle attached at the end of a sentence.
