A crack willow, also known as a brittle willow, is a type of willow tree that is highly susceptible to breaking and cracking under stress. There are a few different synonyms for this particular type of tree, including the term "snapping willow" which refers to its tendency to snap in two under pressure. Other possible synonyms might include "fractured willow" or "cracked willow," both of which highlight the tree's tendency to break apart easily. Overall, these synonyms make it clear that the crack willow is a tree that is particularly vulnerable to physical damage, and that its fragile nature must be taken into account when considering its cultivation and care.