'periodically-constrained' is a modern compound formed from the adverb 'periodically' (from 'periodic') and the past-participle adjective 'constrained' (from the verb 'constrain').

'periodically' derives from Latin/Greek roots via Middle French/Latin compounds (Greek 'periodikos' -> Latin/Medieval forms -> English 'periodic' -> 'periodically'). 'Constrained' comes from Latin 'constringere' -> Old French/Latin-derived forms -> Middle English 'constrain' -> past participle 'constrained'. The compound itself is a recent English formation combining the two elements.

Individually, 'periodically' originally meant 'in regular intervals' and 'constrained' meant 'bound or restricted'; combined in modern usage they mean 'restricted at regular intervals' — the senses of both components are preserved but joined to describe a recurring restriction.