According to theory of electronegativity, most suitable name for ${\mathbf{F}}_2\mathrm{O}$ molecule will be :

Compared to fluorine, oxygen is electropositive in ${\mathrm{OF}}_2$. The names of the electropositive and electronegative elements are written in reverse order. Oxygen has a lower electronegativity than fluorine. Thus, name for ${\mathbf{F}}_2\mathrm{O}$ molecule is oxygen dilfuoride.