noun
urge to defecate; urge to urinate; call of nature
Medical or polite term for the physical sensation of needing to use the toilet. Often used in healthcare contexts or when speaking discreetly.
朝起きるとすぐに便意を感じた。
I felt the urge to defecate as soon as I woke up.
患者は便意を訴えた。
The patient complained of an urge to defecate.
Compound of 便 (べん, 'excrement; convenience') and 意 (い, 'mind; thought; meaning'), literally 'excrement thought' or 'urge related to excretion'. The kanji 便 is used in words related to bodily functions (e.g., 大便, 小便).