Here's what rhymes with unpessimistic.
mystic pessimistic cystic sadistic chauvinistic sophistic artistic holistic mechanistic statistic autistic ballistic logistic theistic animistic hedonistic impressionistic monistic shamanistic surrealistic euphemistic realistic antagonistic optimistic stylistic unrealistic heuristic humanistic journalistic simplistic anachronistic dualistic socialistic synergistic atheistic egoistic fatalistic juristic legalistic novelistic patristic syllogistic egotistic voyeuristic aphoristic belletristic nepotistic linguistic deterministic idealistic materialistic nationalistic naturalistic moralistic narcissistic opportunistic pluralistic rationalistic ritualistic communistic futuristic pantheistic polycystic positivistic eulogistic expressionistic feudalistic inartistic jingoistic pugilistic casuistic puristic characteristic monopolistic altruistic capitalistic paternalistic relativistic imperialistic militaristic monotheistic cannibalistic polytheistic overoptimistic individualistic probabilistic oligopolistic uncharacteristic universalistic spiritualistic sociolinguistic Words that almost rhyme with unpessimistic
flyspeck mimic mythic lipstick lytic dipstick diptych nitpick critic civic lyric acidic parasitic picnic citric cryptic elliptic granitic paralytic physic satiric syphilitic cynic lithic thymic antisemitic gimmick triptych zoophytic sylphic specific scientific analytic clinic rhythmic terrific hemolytic acrylic dendritic ecliptic horrific idyllic limbic pacific rabbinic arthritic empiric haemolytic honorific porphyritic arrhythmic nephritic periwig pinprick encephalitic philippic cenobitic intrinsic apocalyptic catalytic extrinsic phenotypic basophilic hydrolytic impolitic metaphysic neolithic patronymic saprophytic pantomimic juridic bromidic nonrhythmic monolithic nonspecific prolific hemispheric hydrophilic proteolytic unscientific antiarrhythmic organismic thrombolytic megalithic unspecific bulimic hermaphroditic nonscientific coenobitic psychoanalytic logarithmic electrolytic algorithmic eosinophilic fibrinolytic hieroglyphic palaeolithic paleolithic transpacific polyclinic carboxylic cataclysmic stratospheric