This expression is used to state what you consider to be more important than anything else. "First and foremost I want to thank our hosts for their wonderful reception."
For a scholastic author, hardly anything was so likely to precipitate a lengthy disputatio as talk of priority, in its various kinds.
Priority was a major topic of dispute for scholastics
Robert Pasnau (Metaphysical Themes 1274-1671 [2011], 04.3)
If you are out of your depth, you are in a situation which is too difficult for you, or which you know little about. "She started building a website with little computer knowledge, so she was soon out of her depth and had to look for help."
Better to be alone than in bad company.
In the sense of giving a model for the content of a sentence, its representative power, holism is not a theory of meaning; it is the denial that a theory of meaning is possible.
Holism is not a theory of meaning; it is the denial that a theory of meaning is possible
Michael Dummett (The Justification of Deduction [1973], p.309)
Everyone sees what you appear to be, few experience what you really are.