irreplaceabletool
nounUK /ˌɪrɪˈpleɪsəbəl tuːl/
US /ˌɪrɪˈpleɪsəbəl tuːl/
A tool that is so special you can never get another one just like it.
Grandpa's old hammer is an irreplaceabletool because he built our whole house with it.
OTHER MEANINGS
2. A piece of software or equipment that a team cannot work without.
The backup server became an irreplaceabletool for the whole office.
3. A person whose skills are so special that no one else can do their job.
Our coach is an irreplaceabletool for the team's success.
4. An object that holds deep personal meaning and cannot be swapped for a new one.
Her mother's sewing kit is an irreplaceabletool she would never sell.