D defs.my
Entry 1 sense Webster, 1913

Molehill

/mōl'-hĭlˌ/ · Mole·hill · IPA /ˈməʊlhɪl/
01 n. A little hillock of earth thrown up by moles working under ground; hence, a very small hill, or an insignificant obstacle or difficulty; as…
  1. 1.
    A little hillock of earth thrown up by moles working under ground; hence, a very small hill, or an insignificant obstacle or difficulty; as, to make a mountain out of a molehill.
    “Having leapt over such mountains, lie down before a molehill.” South.