"At will" is a commonly used phrase that means "at one's own discretion" or "as one pleases". However, there are several other words and phrases that can be used as synonyms for "at will". Some of these words include "freely", "voluntarily", "unrestrictedly", "spontaneously", and "by choice". Similarly, phrases like "without restraint", "without hesitation", "without limitation", and "without reservation" can also serve as synonyms for "at will". Regardless of the word or phrase chosen, the underlying meaning will always involve doing something according to one's own desire or inclination.