steepen
verb /ˈstiːpən/
  /ˈstiːpən/
[intransitive, transitive]Verb Forms
| present simple I / you / we / they steepen |  /ˈstiːpən/  /ˈstiːpən/ | 
| he / she / it steepens |  /ˈstiːpənz/  /ˈstiːpənz/ | 
| past simple steepened |  /ˈstiːpənd/  /ˈstiːpənd/ | 
| past participle steepened |  /ˈstiːpənd/  /ˈstiːpənd/ | 
| -ing form steepening |  /ˈstiːpənɪŋ/  /ˈstiːpənɪŋ/ | 
- steepen (something) to become or to make something become steeper- After a mile, the slope steepened.