The phrase "imperative color" refers to shades, hues, or tints that possess profound significance or hold an utmost importance in various contexts. Synonyms for this term include "essential shade", conveying the idea that these colors are fundamentally necessary for communication, design, or visual impact. Additionally, you could use the phrase "crucial tint" to emphasize the significance of these hues. Ultimately, all these synonyms point to the profound role that certain colors can play in evoking emotions, conveying messages, or creating impactful visuals, highlighting their significance in multiple domains, from graphic design to art therapy.