1. (n.) Regular change or succession from one thing to another; alternation; mutual succession; interchange\.

2. (n.) Irregular change; revolution; mutation.

adverse circumstances adversity affliction aggravation alteration alternation annoyance asperity blight bummer care chain of circumstances chain reaction change changeability changes chapter of accidents chop and change concatenation of events contrasts cross curse difficulties difficulty diversity downer feast and famine fluctuation flukiness flux hard knocks hard life hard lot hardcase hardness hardship inconstancy innovation ins and outs irritation mischance misfortune mutability mutation novelty oscillation pendulation permutation plight predicament pressure progression reversal rigor sea of troubles seesawing shifting shuffling sport stress stress of life teeter-tottering teetering tottering transposition trial tribulation trouble troubles unpredictability ups and downs vacillation vale of tears variability variation variations variety vicious circle vicissitudes vicissitudes of fortune wavering