Knot up (5)
I believe the answer is:
gnarl
(Other definitions for gnarl that I've seen before include "Lump, growl" , "Something lumpy" , "Rough lump (on a tree)" , "lump of wood" , "Tree-swelling" .)
I believe the answer is:
gnarl
(Other definitions for gnarl that I've seen before include "Lump, growl" , "Something lumpy" , "Rough lump (on a tree)" , "lump of wood" , "Tree-swelling" .)