i Register
In some senses, insistent is marked as obsolete. Watch for register when choosing this word.
VERBS
be | become, grow | remain
ADV
extremely, most, very
He was extremely insistent about arriving at the airport three hours early for his flight.
fairly, quite
PREP
about
He remained insistent about finishing the project before the deadline arrived.
on/upon
She was insistent upon finishing the project before the deadline, no matter what obstacles appeared.