composer remove vendor/package
Syntax: composer remove <package>
Example: composer remove laravel/tinker
Delete the file composer.phar.
Delete the Cache Folder:
Linux: /home/<user>/.composer
Windows: C:Users<username>AppDataRoamingComposer
On windows:
rmdir /s /q ComposerSetup
rmdir /s /q C:Users<username>AppDataRoamingComposer