Here are some synonyms for querulous:
* Grumbling
* Whining
* Petulant
* Cantankerous
* Fretful
Here are some examples of how you might use the word "querulous" in a sentence:
* "The old man sat on the park bench, muttering querulous complaints about the noisy children."
* "Her querulous voice was getting on everyone's nerves."
* "The querulous tone of his letter made it clear he wasn't happy with the situation."