Replace, displace, supplant, supersede are rarely interchangeable terms, but they can carry the same basic meaning—to put a person or thing out of his or its place or into the place of another.
Replace implies supplying a substitute for what has been lost, destroyed, used up, worn out, or dismissed or it may imply a preferring of one of two or more things that could satisfy a need and sometimes it implies a putting back into a proper or assigned place.
Displace implies a dislodging, ousting, or putting or crowding out followed by a replacing. This dual implication of putting out of place and of replacing is the chief distinction of displace in contrast with replace . However one of these ideas is sometimes stressed more than the other so that the emphasis is either on ousting or on replacing.
Supplant basically implies a dispossessing or ousting by craft, fraud, or treachery and a taking or usurping of the place, possessions, or privileges of the one dispossessed or ousted.
But supplant sometimes implies an uprooting and replacing rather than a dispossessing and usurping; in such cases trickery or treachery is no longer implied <his tutor tried to supplant his fears by arousing his sense of curiosity> <don’t claim that the Divine revelation has been supplanted … but that it has been amplified —Mackenzie > <the architect, to serve the vogue, uptilts greenhouses thirty stories high on stilts, supplanting walls of stone with sheets of glass —Hillyer >
Supersede implies a causing of another to be set aside, abandoned, or rejected as inferior, no longer of use or value, or obsolete <the old-fashioned fishing luggers with their varicolored sails have been superseded by motorboats —Amer. Guide Series: La. > <that is the worst of erudition—that the next scholar sucks the few drops of honey that you have accumulated, sets right your blunders, and you are superseded —Benson >