Like alkyl groups are electron releasing groups, are aryl groups electron releasing or electron withdrawing group?

Aryl groups could be electron donating or withdrawing depending on the kind of substituent that is attached to the ring.If we only consider the Phenyl group, it’s an electron withdrawing ring that is triggered by induction(-I effect).This is evident from the pKa numbers of Acetic acid (pKa 4.75) and benzoic acid ( pKa 4.2).
But, phenyl groups can be either an electron-donating group or electron withdrawing through resonance.
e.g: benzyl cation & benzyl anion.

Hope it helps!