Otsukaresama (お疲れ様): an expression that acknowledges another person’s effort. At work, it is also said to a colleague who leaves before others. It can be said to colleagues and to superiors.
Isshōkenmei (一生懸命): with all one’s might. It grew out of the older isshokenmei (一所懸命), which described a medieval warrior who staked his life on a single landholding.