Select the INCORRECTLY spelt word.

Accelarate

The incorrectly spelt word in the given options is "Accelarate." The correct spelling is "Accelerate."

Here are the correct spellings and definitions of the words:

• Calibrate: To adjust or measure the accuracy of something.
• Accelerate: To increase in speed or rate.
• Proliferate: To increase rapidly in number or extent.
• Insinuate: To suggest or imply something indirectly or subtly.