FromBASE(“building, antenna-tower, span, earth”) +‎jump.

BASEjump (pluralBASE jumps)

1. Aparachutejump from afixedpoint rather than from anaircraft; typically from atallbuilding,highbridge orrockformation.

BASEjump (third-person singular simple presentBASE jumps,present participleBASE jumping,simple past and past participleBASE jumped)

1. (intransitive) To make such a jump.
   • 2015 October 2, Veronica Rocha, “BASE jumper Johnny Strange dies in wingsuit jump in Swiss Alps”, inLos Angeles Times‎^[1]:

     Adventurer Johnny Strange, who grew up in Malibu, was killed Thursday when he crashed while wingsuitBASE jumping in the Swiss Alps.

• BASE jumper