The phrase "whitish-yellow" describes a pale shade that has hints of yellow in it. Some synonyms for this phrase could include the terms "cream-colored", "ivory-toned", and "off-white with a yellowish tint". The term "pale gold" might also be considered a synonym, as well as "buttercream", "vanilla" or "saffron-tinged". Depending on context, other synonyms could include "yellowish-white", "pale yellow", "lemon hued" or "blonde-toned". The nuances of the particular shade being described should be taken into account when selecting a synonym, and the decision should be made based on the specific effect the writer wishes to achieve.