differ, v. be [unlike]; [disagree]. Antonyms: [agree], concur.
difference, n. dissimilarity, [unlikeness], [distinction], [variation], [contrast], discrepancy, [discrimination], disparity, [diversity], dissimilitude, incompatibility, [inequality], heterogeneity, [variety]; dissension, [variance]. See disagreement. Antonyms: [uniformity], [similarity], agreement consonance, [correspondence], indiscrimination, promiscuity, identity.
different, a. [dissimilar], [unlike], [contrary], [opposite], contrasted, variant, [diversified], [manifold], [various], [diverse], [sundry], incompatible, heterogeneous, [nondescript], miscellaneous [unclassifiable], [unique]. Antonyms: [similar], [like], [same].
differentiate, v. discriminate.
differentiation, n. [discrimination].
difficult, a. [arduous], [onerous], [complicated], [intricate], [hard]; uncompliant, intractable, [perverse], [fastidious], [exacting]. Antonyms: facile, [light], [easy].
difficulty, n. [obstacle], [impediment], [obstruction]; arduousness, [hardness]; [controversy], [disagreement], [objection], [cavil]; predicament, [quandary], [dilemma]. Antonyms: [ease], facility, extrication, [release].
diffidence, n. [timidity], [bashfulness].