What is a synonym for the term 'rallentando' in musical context?

In musical terminology, 'rallentando' refers to a gradual slowing down of the tempo. This effect is often used to create a sense of relaxation or to prepare for a transition in the music. The correct response, which is 'slowing down,' directly captures the essence of what 'rallentando' means, as it describes the action being taken in terms of tempo.

While other choices might reflect different musical terms or actions, they do not convey the same meaning as 'rallentando.' For example, 'accelerando' indicates a speeding up of the tempo, which is the opposite of what 'rallentando' signifies. 'Ad libitum' refers to performing at one's discretion, potentially varying tempo or phrasing, but it does not specifically denote slowing down. 'Gradually increasing' also contradicts the intention of 'rallentando,' as it implies a rise in tempo rather than a decrease. Thus, 'slowing down' is the most accurate synonym in this context.