Which one of the following is correctly spelled word?

acquaintance

The only correctly spelled word in your list is acquaintance. The other words are misspelled as follows:

• Accellerate is spelled with two l's instead of one. The correct spelling is accelerate.
• Aggressor is spelled with two g's instead of one. The correct spelling is aggressor.
• Recieved is spelled with two e's instead of one. The correct spelling is received.