involution

(n) reduction in size of an organ or part (as in the return of the uterus to normal size after childbirth)
(n) a long and intricate and complicated grammatical construction
(n) marked by elaborately complex detail elaborateness, intricacy, elaboration,
(n) the act of sharing in the activities of a group
- the teacher tried to increase his students' engagement in class activities
involvement, participation, engagement,
(n) the process of raising a quantity to some assigned power exponentiation,
(n) the action of enfolding something enfolding,

elaborateness intricacy elaboration involvement participation engagement exponentiation enfolding

non-engagement non-involvement nonparticipation

involutional depression