Definitions:
a set of software features and hardware devices (such as windows, icons, mice, and pull-down menus) designed to simplify or demystify computing operations for the user

a hypothetical subatomic particle of large mass which interacts only weakly with ordinary matter, postulated as a constituent of the dark matter of the universe.

a weak and cowardly or unadventurous person.

fail to do or complete something as a result of fear or lack of confidence