installment
They were paying for their house in installments of $2,000 a month for three years.
institutional
The old man is in need of institutional care.
intent
The court has to decide if he，entered the building with intent to steal.
intervene
The government had to intervene in the strike.
intricate
The whole case is very intricate. The lawyers have to handle it very carefully.
invalid
Your ticket has passed its expiry date, so it is now invalid.
invariably
The security guards are invariably ex-service men.
investigator
The investigators recessed for lunch.
investor
Some investors will take losses, some organizations will fail
but the overall economy and the market are healthy enough to absorb all this negative effects.