2017年8月11日金曜日 - Jumat, 11 Agustus 2017- Friday, August 11th, 2017

I'm sorry to say, the antonym of 'curam' is not 'terjal' or 'tanjak'. It's 'landai', 'berjenjang' atau 'bertahap', dalam pengertian sebuah landaian/bidang atau dalam proses disebut juga bertahap.

Explanation:

This is obviously, NOT 'terjal' or 'tanjak' or 'curam'.

This is called 'sudut tajam' in Indonesian. (Seen from the perspective of the angle, meanwhile, seen from the overall perspective, the person who is travelling the angle, it's GRADUAL).

This is 'terjal' in Indonesian language.