gnarl

1. something twisted and tight and swollen;

"their muscles stood out in knots"

"the old man's fists were two great gnarls"

"his stomach was in knots"

1. twist into a state of deformity;

"The wind has gnarled this old tree"

2. make complaining remarks or noises under one's breath;

"she grumbles when she feels overworked"