Proportion adjectives are listed in this post. Each word below can often be found in front of the noun proportion in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing PROPORTION.
above, absolute, actual, adequate, admirable, alarming, ample, annual, appreciable, appropriate, arithmetical, artistic, average, balanced, beautiful, best, better, big, certain, common, competent, considerable, constant, continued, convenient, correct, corresponding, definite, desired, different, diminished
direct, divine, double, due, e, enormous, epic, epidemic, equal, equitable, equivalent, exact, excessive, exquisite, extraordinary, fair, fine, first, fit, fixed, following, former, full, further, general, generous, geometric, geometrical, gigantic, good, goodly
great, greater, greatest, harmonious, healthy, heavy, high, higher, highest, historic, huge, human, ideal, ill, immense, important, in, inconsiderable, increasing, infinitesimal, insignificant, just, laige, large, larger, largest, largo, last, least, less, lesser
liberal, like, limited, little, low, lower, lowest, m, major, mathematical, maximum, mean, minimum, minor, minute, moderate, modest, moral, more, musical, natural, necessary, negligible, new, nice, normal, notable, numerical, observed, ordinary, original
other, overall, overwhelming, own, particular, perfect, possible, precise, present, proper, ratable, rateable, real, reasonable, reciprocal, regular, relative, requisite, respectable, respective, reverse, right, rough, same, significant, similar, simple, single, sizable, sizeable, slight
small, smaller, smallest, specific, strict, substantial, such, sufficient, suitable, symmetrical, tiny, total, trifling, true, undue, unequal, unfair, uniform, unknown, unusual, usual, variable, vast, very, whole
Hope this word list had the adjective used with proportion you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.