How to Disable a Yum Repository

To disable a Yum repository, run the following command as root:

yum-config-manager --disable repository…

…where repository is the unique repository ID (use yum repolist all to list available repository IDs). Similarly to yum-config-manager --enable,

you can use a glob expression to disable all matching repositories at the same time:

yum-config-manager --disable glob_expression…

When successful, the yum-config-manager --disable command displays the current configuration.

Source: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/sec-managing_yum_repositories