flexion

1. The act of bending a joint, especially a bone joint; the counteraction of extension. (countable, uncountable)
2. The state of being bent or flexed. (countable, uncountable)
3. Deviation from straightness. (countable, uncountable)
4. The variation of words by declension, comparison, or conjugation; inflection. (countable, dated, uncountable)

الجمع flexions