indissoluble
/ˌɪndɪˈsɑːljəbəl/
adjective
- Impossible to break apart, dissolve, or end; lasting and strong.
- The material is indissoluble in water, making it ideal for waterproof coatings.
- They formed an indissoluble bond during their years of travel.
- The indissoluble union of the two companies created a market leader.