1. fail to notice something
overlook a mistake/error
When you overlook something means to fail to notice it or to fail to give it proper attention. "I seem to have overlooked that part of the report." it can also mean to have a view of something usually from above. "I would like to book a room overlooking the lake if possible." "The sky bar offers views that overlook the entire city." If you 'overlook' someone's behaviour or comments it means you choose to ignore them. "I can't overlook that comment I find it very offensive."