Synonyms for Intentional (same or very similar meaning)
WordNet sense 1 (done by design):
wilful, willful
WordNet sense 2 (of your own free will or design; not forced or compelled):
voluntary
WordNet sense 3 (done or made or performed with purpose and intent):
designed
WordNet sense 4 (by conscious design or purpose):
deliberate, knowing, deliberate
WordNet sense 5 (intentional or planned):
intended
From the ODE community, based on WordNet
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