The letter K has several synonyms that are commonly used in different contexts. One of the most widely recognized synonyms for the letter K is the word "kilo," which is used to denote a unit of measurement for weight. Another synonym for the letter K is the word "keen," which is typically used to describe someone who has a sharp intellect or is highly perceptive. Additionally, the letter K is frequently identified with the color "khaki," which is a shade of brown commonly used in military uniforms. Other synonyms for the letter K include "kangaroo," "kinetic," and "knight," each of which is associated with different meanings and contexts.