variable >> ˈvɛːrɪəb(ə)l
Definition: [adjective] not consistent or having a fixed pattern; liable to change.
Example: the quality of hospital food is highly variable
Definition: [adjective] able to be changed or adapted.
Example: the drill has variable speed
Definition: [noun] an element, feature, or factor that is liable to vary or change.
Example: there are too many variables involved to make any meaningful predictions