cold-shoulder, neglect, dismiss, brush aside, slight, discount, disregard, cut, snub, brush off, more...

acknowledge, notice, heed, observe, attend

selective attention, change blindness, attentional blink, more...

not acknowledge,   pay no heed to,   don't bother,   not consider,   let it slide,   brush it off,   not recognize,   not pay attention,   openly disregards,   doesn't consider