adjective:

a. full of complaints; habitually complaining.

b. always eager to complain.

c. showing a complaining attitude.

Example sentences:

1. The customer gave querulous comments about the price of her products.

2. "Clean up your room!" my mom said in a querulous voice.

3. The customer spoke in a querulous tone when the cashier didn't give her a discount.

Querulous is from a word meaning quarrelsome and now means complaining, whining, moaning, or peevish

e.g. The old woman spoke in a very querulous manner, complaining about the weather, the prices, the government and everything she had contact with.