あんまり
あんまり · anmari · JLPT N3 · noun
not very
Casual form of あまり (余り, excess): not in excess = not much
あまり comes from 余る, to be left over or in excess. With a negative verb it means not to any excess, so not very or not much. Adding ん makes it more casual and emphatic: あんまり好きじゃない means I don't like it much.