to one's heart's content; as much as one likes; freely
Used when someone does something without restraint, fully enjoying or indulging in an activity. Often used with verbs like 楽しむ, 語る, 泣く, etc.
I enjoyed the holiday to my heart's content.
I cried as much as I wanted.
存分に is a shorter, slightly more formal way to say 'as much as one likes', while 思う存分 is the more common everyday phrase.
存分に means doing something as much as one likes or is satisfied with, while とことん implies pushing on to an absolute limit even against difficulty.
存分に is a more formal, polished way to say 'to one's heart's content', while 思いっきり is casual and more emphatic.
存分に means doing something to one's heart's content without restriction, while どしどし specifically encourages someone to act boldly and without hesitation.
存分 (ぞんぶん) means 'as much as one thinks', from 存 (think) and 分 (portion). The adverbial form 存分に is used to mean 'to one's heart's content'.