Q.What is meant by wattless current?

Resolving the current phasor. In an AC circuit where voltage leads current by phase angle $\phi$, the current phasor $I_{RMS}$ can be resolved into two perpendicular components relative to the voltage direction: $I_{RMS}\cos\phi$, lying ALONG (in phase with) the voltage, and $I_{RMS}\sin\phi$, PERPENDICULAR to it.

Active (wattful) vs reactive (wattless) components. The in-phase component, $I_{RMS}\cos\phi$, delivers power $V_{RMS}I_{RMS}\cos\phi$ -- matching the ordinary average-power formula exactly -- so it is called the active or 'wattful' current: it is the only part of the total current doing genuinely useful electrical work. The perpendicular component, $I_{RMS}\sin\phi$, has a $90^{\circ}$ phase relationship to the voltage, and since power averaged over a cycle for a $90^{\circ}$-shifted pair is always exactly zero, this component delivers zero net power -- called the reactive or 'wattless' current. …