A walk in the park is something pleasantly easy. It was no walk in the park.
It is used in the negative far more often than in the positive, to say how hard something was. It compares the task with the easiest pleasant thing anybody could think of.
1phrasewalk in the parkSomething pleasantly easy.
“After the first winter, the second was a walk in the park.”
walk in the park is a phrase.
Practised in Idioms