noun

a person or thing that gives rise to an action, phenomenon, or condition.

the cause of the accident is not clear

source,root,origin,beginning(s),starting point,seed,germ,genesis,agency,occasion,mainspring,base,basis,foundation,bottom,seat,originator,author,creator,producer,agent,prime mover,maker,fons et origo,fountainhead,wellspring,fount,begetter,radix

verb

make (something, especially something bad) happen.

this disease can cause blindness

bring about,give rise to,be the cause of,lead to,result in,create,begin,produce,generate,originate,engender,spawn,occasion,effect,bring to pass,bring on,precipitate,prompt,provoke,kindle,trigger,make happen,spark off,touch off,stir up,whip up,induce,inspire,promote,foster,beget,enkindle,effectuate