uppermost
adj. C2 Proficiency US //ˈəpɝˌmoʊst// UK //ˈʌpəmˌəʊst// up·per·most
adj. most important or the one that is on the top. You use it to describe the thing that is most in your mind or the highest part of something.
adj. most prominent in the mind or most important in significance; alternatively, situated on the top or upper part of something. Often used in the phrase 'uppermost in one's mind'.
The safety of the children is uppermost in my mind.
When planning the new office layout, the architect ensured that the uppermost priority was natural light and open space.
While the technical specifications were impressive, the uppermost concern for the board remained the long-term sustainability of the project and its impact on the local community.
From Middle English upper-moste; equivalent to upper + -most.