(onomatopoeic) imitating a small animal's cry, particularly a kitten or small bird
"Meep, meep, meep!" echoed his brothers and sisters. They all felt pleased with themselves for having learnt to call their mother … ???, Viktor Astafyev, Meep the Baby Martin, published in Soviet Literature: Issues 7-12 in 1983
'Granny, your hat squeaked,' said Tiffany. 'It went meep!'
'No it didn’t,' Granny said sharply.
'It did, you know,' said Nanny Ogg. 'I heard it, too.'
Granny Weatherwax grunted and pulled off her hat. The white kitten, curled around her tight bun of hair, blinked in the light. 2006, Sir Terry Pratchett, Wintersmith; Corgi edition, published in 2007, page 222
"We gave him three nervous breakdowns, you know," he says, waving his fingers in the rear view.
"Listen, I..."
"I've heard this kind of thing before. The English think the French are little blind dogs. Meep meep meep meep meep," he says, performing a talking pantomime with his hand. 2006, Dave Bidini, The Five Hole Stories, page 62:
(onomatopoeic) imitating a small vehicle's high pitched horn
(informal, onomatopoeic) expressing surprise, dismay, fear, or concern
(informal, onomatopoeic) A high-pitched exclamation of fear or concern.
Gilly cradled her daughter close, even when the baby let out a “meep” of protest before getting back to the business of nursing. 2013, Megan Hart, Precious and Fragile Things, page 407:
(informal, onomatopoeic) To make a high-pitched exclamation.
Her companions gathered round her, twittering and meeping sympathetically, but there was nothing that anyone could do. 1968, Arthur C. Clarke, 2001: A Space Odyssey, I Primeval Night, 2 The New Rock, page 11
"See that guy down there?" Jonathan asked, and tilted my chair up on its front legs to give me a better view. I meeped and clutched the chair arms harder. "No? Well, okay, granted, they all look alike from up here. Here, I'll help." My forehead touched the glass. It rippled like water, and I melted right through the slick, cold surface, [...] 2005, Rachel Caine, Chill Factor, page 103:
He cried out, as if he meant it as a joke, "When I was Richard's age I nearly died of pneumonia." "Darling, it is cold," Ariah meeped, and put her mitten on his. 2005, John Gardner, October Light, page 126:
Rith stayed where he was, watching the silhouette of the cat in the darkness. She sat perfectly still and watched him back. Then she meeped and looked at the stairs. 2007, Pat Schmatz, Circle the Truth, page 188: