Definition from Wiktionary, the free dictionary
Alternative forms 
crabapple (plural crabapples)
- Any of the wild varieties of apple tree, genus Malus, which generally yield small, bitter fruit (in comparison to domestic apples, Malus domestica.
- The fruit of this tree.
- An unpleasant person; a person who is crabby.
Derived terms 
terms derived from crabapple