Synonyms for Insistent (same or very similar meaning)
WordNet sense 1 (demanding attention):
crying, exigent, instant, clamant
WordNet sense 2 (requiring attention or action):
imperative
WordNet sense 3 (persistently continual):
repetitive
WordNet sense 4 (seemingly without interruption; chiefly restricted to what recurs regularly or frequently in a prolonged and closely spaced series):
continual
From the ODE community, based on WordNet
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