Learner's definition of LIMB
2 : a large branch of a tree
out on a limb
: in or into a risky or dangerous position or situation
She went out on a limb to help you. [=she took a chance; she did something that meant she could be criticized or harmed in some way]
If you try to oppose the boss yourself, you're likely to get caught out on a limb.
tear (someone) limb from limb
: to attack or kill (someone) in a very violent way