effortless
adj.describing something that looks very easy to do, even if it is actually difficult. It shows that someone has a lot of skill or natural talent.
adj.appearing to require little or no physical or mental exertion. Often used to describe a performance or action that masks the underlying skill or hard work involved.
“She makes playing the piano look effortless.”
“The athlete won the race with an effortless stride, barely looking tired as he crossed the finish line.”
“The author's effortless prose hides the fact that she spent years meticulously editing every sentence to achieve such a natural flow.”
Typically used attributively before a noun or predicatively after a linking verb like 'seem' or 'look'.
“Learning new systems is not effortless , even when the change is ultimately for the better.”
“When everything’s working smoothly, swallowing feels effortless, but it is one of the most complex actions the human body performs.”
From effort + -less.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.