Semplice
Simple, plain.
What it means
Semplice is an Italian performance direction meaning 'simple' or 'plain.' It calls for an uncomplicated, clear delivery without exaggerated embellishment or technical showiness.
Unlike purely characterful directions, semplice emphasizes above all the manner of execution itself: straightforward, unadorned, and without unnecessary additions.
Musical use
Semplice is often used for melodies that, despite possible technical demands, should be delivered calmly and clearly, for instance song-like themes that should not be altered by extra rubato or exaggerated dynamics.
Semplice should be distinguished from schietto, which has a similar meaning but emphasizes more the character of being 'unadorned, direct,' whereas semplice points more toward technical and structural simplicity of execution.
Performance practice
Play semplice passages with a clear, straightforward touch, avoiding added ornaments or pronounced rubato. Let the melody speak for itself, without overloading it interpretively.