On a volume-profile, high volume nodes appear as wide bulges. They represent prices that both sides found acceptable for a long time, which means a lot of inventory exists there.
Price entering a high volume node typically slows and chops, because there is plenty of activity at every tick. That makes these poor areas for breakout entries and reasonable areas for targets, since momentum usually stalls on arrival.
The corollary is low-volume-node, where price tends to move fast. Using nodes this way is one of the more practical applications of volume data: it says nothing about direction but a fair amount about likely speed.
Related: low-volume-node, volume-profile, point-of-control, naked-poc, balance-area