bout
Synonym discussion
Sense: noun/1
For sense 1, 'bout' suggests a limited stretch of time when something fairly strong happens, often illness or something unpleasant. 'Spell' is the closest everyday choice and works well for weather, dizziness, or sadness. 'Episode' is more formal and often sounds medical, especially when it means one event in a repeated pattern. 'Attack' is stronger and more sudden, so it fits pain, coughing, or fear better than ordinary activities. 'Phase' is usually longer and calmer, often describing a stage rather than a sharp spell. You can say 'a bout of flu' or 'a bout of crying', but 'a phase of flu' sounds wrong, and 'an attack of studying' does too.
Etymology
Originally, bout referred in regional English to one out-and-back turn made while plowing a field. That use came from Middle English 'bought', meaning a bend or curve. From the idea of turning and coming back, the word later developed the sense of one short spell or one contest.