Definitions:
having an even and regular surface; free from perceptible projections, lumps, or indentations

(of movement) without jerks

(of an action, event, or process) without problems or difficulties

(of a person or their manner) suavely charming in a way regarded as possibly insincere

(of food or drink) without harshness or bitterness

give (something) a flat, regular surface or appearance

deal successfully with (a problem or difficulty)

in a way that is without difficulties