1. more inclined to complain or express dissatisfaction; more prone to grumbling
Usage: comparative form of grumbly

Examples

• He became grumblier as the day went on without a break.
• The grumblier customers were the ones who had waited longest in line.
• She felt grumblier than usual after a poor night's sleep.
• The team grew grumblier with each loss during the season.
• My grandfather is grumblier in winter when the weather is cold and dark.