falter

The story

1. North Germanic · derived from
2. Middle English · inherited fromfalteren“to stagger; be unsteady, tremble, quiver; to stammer; be entangled, get caught”
3. English todayfalter

From Middle English falteren (“to stagger; be unsteady, tremble, quiver; to stammer; be entangled, get caught”), further origin unknown. Probably from a North Germanic source such as Old Norse faltrask (“to hesitate, be puzzled, be encumbered”). May also be a frequentative of fold, although the change from d to t is unusual.