ˈdüə(r), ˈdu̇(ə)r, ˈdu̇ə noun
( -s )
Etymology: Middle English, from don to do + -er — more at do
1. : one that does : one that performs or executes
a thinker or a doer — Sinclair Lewis
2. : a domestic animal considered in terms of its capacity to respond to proper care and feeding — used with a qualifying adjective
those steers are very poor doers
it doesn't pay to hold over any but your best doers
3. Australia : eccentric