subtle
US /ˈsʌt̬.əl/
UK /ˈsʌt̬.əl/

1.
sutil, delicado, imperceptible
so delicate or precise as to be difficult to analyze or describe
:
•
The painting had a subtle blend of colors.
La pintura tenía una mezcla sutil de colores.
•
There was a subtle change in his expression.
Hubo un cambio sutil en su expresión.
2.
astuto, perspicaz, ingenioso
making use of clever and indirect methods to achieve something
:
•
He used a subtle approach to persuade them.
Utilizó un enfoque sutil para persuadirlos.
•
Her subtle hints were finally understood.
Sus sutiles indirectas finalmente fueron comprendidas.