"Gruntled" is a relatively uncommon word, often used in a humorous or satirical sense to imply contentment or satisfaction. While there are few direct synonyms for "gruntled", there are several related words that capture similar sentiments. One might describe feeling pleased, happy, or contented. Other options could include satisfied, fulfilled, or gratified. If the sense of contentment stems from a particular achievement or success, one might use words like accomplished, triumphant, or successful. Ultimately, the choice of word will depend on the context and specific emotion being conveyed.