Asexual describes little or no sexual attraction. See the full Asexual Spectrum page.
Aromantic describes little or no romantic attraction. See the full Aromantic Spectrum page.
The Split Attraction Model treats sexual and romantic attraction as two separate axes, so a person can be one, both, or neither. Someone can be asexual and still experience romantic attraction (for example, a heteroromantic asexual person), and someone can be aromantic and still experience sexual attraction.
Where both overlap, Aroace describes the combined experience - not simply "extra asexual" or "extra aromantic," but its own distinct identity with its own flag.