Definition of moo in English:



[no object]
  • Make the characteristic deep resonant vocal sound of cattle.

    ‘the cows mooed from the barn’
    • ‘The rains began to pour down in heavy pelts, in huge droplets, the cows mooing a nervous call loud over the plateau.’
    • ‘Several of the bulls started bellowing and the cows mooing.’
    • ‘Children were running everywhere, dogs were barking and cows were mooing.’
    • ‘We drove down a winding country road surrounded by large vegetable gardens in various stages of harvest, cow pastures with lots of passive cows mooing softly and small rural homes.’
    • ‘It was sleeping peacefully, mooing faintly and twitching its hooves.’
    • ‘Cattle and sheep started to roam languidly towards the hill slopes where they grazed, mooing and baaing.’
    • ‘Adding to the mesmerizing murmur of the flowing water, the sounds of birds singing and cows mooing left one feeling totally at peace.’
    • ‘She mooed loudly as though in shock, and ran in the opposite direction.’
    • ‘I reached out to stick a finger into the pail when the cow mooed again.’
    • ‘Disturbed by Lewis's examination of her newborn, the heifer mooed unhappily.’
    • ‘Quietly waiting, chewing their cuds, occasionally mooing, they look in from outside their barn doors at the plentiful picnic refreshments prepared for the human beings.’


  • 1The characteristic sound of cattle.

    ‘the doleful moo of a cow’
    • ‘Milking takes a few minutes, the suckers are taken off, and the next row of cows files in with hardly a moo to be heard.’
    • ‘When I reached the gate, I heard happy moos and clucks from the cows and chickens.’
    • ‘Rows and rows of cows and heifers, their moos resounding within the school walls, were tethered to makeshift stalls.’
    • ‘Half of the cows were missing from the field, and you could occasionally hear a moo from a random direction.’
    • ‘All the other campers were gone to either river raft or kayak, and the campground was totally quiet, all you could hear were the crickets and an occasional moo from a cow.’
    • ‘All I could hear, for half a mile, was the sound of our feet crunching on the gravel, and the gentle moos coming from the cows in the fields.’
    • ‘He smiled, puckered his lips and let out a deep moo.’
    • ‘Costing £9.99, the cow moos and shakes uncontrollably when switched on.’
  • 2British informal An irritating or incompetent woman.

    ‘you silly old moo’
    • ‘There is, finally and thankfully, a murder and one of the silly, uptight moos gets locked up.’
    • ‘It has been some time since my last e-mail, and I've been a lazy moo and not spoken to anyone since.’
    • ‘She thinks the stupid moo is acting in an understandable fashion.’
    • ‘Grace was given the chance to redeem herself and the silly moo didn't take it’


Mid 16th century: imitative.