to bleach / to decolorize
de-ko-lo-RA-re
Decolorare is a regular -are verb. 'Decolorazione' is the noun (bleaching/decolorization).
Ha decolorato i capelli prima di tingerli.
She bleached her hair before dyeing it.
Il cloro decolora i tessuti colorati.
Chlorine bleaches colored fabrics.