gnarl

(noun) something twisted and tight and swollen. Synonyms: knot. Examples: "Their muscles stood out in knots." "The old man's fists were two great gnarls." "His stomach was in knots."

(verb) twist into a state of deformity. Example: "The wind has gnarled this old tree."

(verb) make complaining remarks or noises under one's breath. Synonyms: murmur, mutter, grumble, croak. Example: "She grumbles when she feels overworked."