verb

make or become deep or deeper.

the crisis deepened

grow,increase,intensify,strengthen,escalate,mushroom,snowball,add to,heighten,reinforce,enhance,boost,magnify,amplify,augment,enrich,promote,encourage,exacerbate,aggravate,inflame,worsen,make/become worse,hot up,step up,dig out,make deeper,dig deeper,scoop out,scrape out,hollow out,excavate