c. 1200, from Old English hleapan "to jump, spring clear of the ground by force of an initial bound; run, go; dance, leap upon (a horse)" (class VII strong verb; past tense hleop, past participle hleapen), from Proto-Germanic *hlaupanan (source also of Old Saxon hlopan, Old Norse hlaupa, Old Frisian hlapa, Dutch lopen, Old High German hlouffan, German laufen "to run," Gothic us-hlaupan "to jump up"), of uncertain origin, with no known cognates beyond Germanic; perhaps a substratum word.
First loke and aftirward lepe [proverb recorded from mid-15c.]
Transitive sense "pass over by leaping" is from early 15c. Leap-frog, the children's game, is attested by that name from 1590s ("Henry V"); figurative use by 1704; as a verb from 1872. To leap tall buildings in a single bound (1940s) is from the description of Superman's powers. Related: Leaped; leaping.