donkey
don‧key /ˈdɒŋki $ ˈdɑːŋki/
noun
1. [countable] a grey or brown animal like a horse, but smaller and with long ears
2. donkey’s years British English spoken a very long time
for donkey’s years
I’ve had this jacket for donkey’s years.
don‧key /ˈdɒŋki $ ˈdɑːŋki/
noun Date: 1700-1800
Origin: Perhaps from dun (=gray-brown) + -key (as in monkey)
Origin: Perhaps from dun (=gray-brown) + -key (as in monkey)

1. [countable] a grey or brown animal like a horse, but smaller and with long ears
2. donkey’s years British English spoken a very long time
for donkey’s years