at heart prepositional phrase2 •In spirit; according to one's beliefs, views or feelings; deep down, fundamentally, really.I’m a vegan at heart – the thought of the death of animals for my food is abhorrent.My dad may be old on the outside, but he’s young at heart; he plays video games every now and then to improve his coordination. •Wished earnestly for; held in high esteem.I always have your best interests at heart.
