A+아/어지다 ~ To get or become A

Adding +아/어지다 to a adjective stem allows it to change to “become A” or “get A”

Examples
좋아요 –> 좋아져요
become/get better
추워요 –> 추워져요
become/get cold
슬프요 –> 슬프져요
become/get sad
-져요 can also be changed to 졌어요 for past tense
똑똑해졌어요
became/got smarter
똥똥해졌어요
became/got fat
나빠졌어요
became worse or got bad
It can also be used for the future tense, by using -질 거에요 (as 져요 is an abbreviation of 지어요)
나빠질 거에요
will become worse/bad
더워질 거에요
will become hot