Q: When you’re grateful, what exactly are you full of?
A: You’re full of gratitude, of course. But what you’re really asking is, what is “grate”?
The “grate” that a “grateful” person is full of, according to John Ayto’s Dictionary of Word Origins, “is a now obsolete adjective, meaning ‘pleasing’ and ‘thankful.’ ”
The old modifier—derived from gratus, a Latin adjective meaning agreeable, pleasing, or thankful—had its heyday in the 1500s and 1600s, according to citations in the Oxford English Dictionary.
“Grateful is a curious sort of adjective,” Ayto writes. “It is unusual for adjectives ending in -ful themselves to be formed from adjectives, and it has been suggested in this case that the related Italian gradevole ‘pleasing’ may have had some influence.”
The OED notes that the Italian word was also spelled gratevole, and that the English usage may have been influenced by “an accidental resemblance” between the Italian -vole and the English “-ful” endings.
In the 16th and 17th centuries, Oxford says, “grateful” was one of several new words that showed up in English with adjectives attached to the suffix “-ful.” Others were “direful,” “tristful,” and “fierceful.”
The Latin adjective gratus has given English several other words, including “gratify,” “gratitude,” and “gratuity.” And the related Latin noun gratia (grace, kindness) has given English “grace” and “gratis.”
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