| Interlingue | ile-000 |
| constant | |
| English | eng-000 | confirmed |
| English | eng-000 | constant |
| English | eng-000 | invariable |
| English | eng-000 | permanent |
| English | eng-000 | perpetual |
| English | eng-000 | settled |
| English | eng-000 | standing |
| English | eng-000 | steadfast |
| English | eng-000 | steady |
| English | eng-000 | unfailing |
| English | eng-000 | unwavering |
| Interlingue | ile-000 | firm |
| Interlingue | ile-000 | fix |
| Interlingue | ile-000 | frequent |
| Interlingue | ile-000 | loyal |
| Interlingue | ile-000 | permanent |
| Interlingue | ile-000 | perpetui |
| Interlingue | ile-000 | resolut |
| Interlingue | ile-000 | sobri |
| Interlingue | ile-000 | tranquil |
| Interlingue | ile-000 | íncessant |
| Interlingue | ile-000 | ínfallibil |
| Interlingue | ile-000 | ínhesitant |
| Interlingue | ile-000 | ínvariabil |