The Brazilian was accused of feigning injury after being kicked by Celtic skipper Scott Brown in this month's Champions League clash at Parkhead.
Brown was red-carded for lashing out at the striker.
But the player was barracked by the home crowd for writhing in agony on the ground.
Celtic boss Neil Lennon slammed Neymar's antics and he was joined in his condemnation by Chelsea boss Jose Mourinho.
But Adriano has rounded on the 21-year-old's critics. He said: "Neymar is not an actor, he does not dive - people are looking for it because they know it from Brazil.
"There have been fouls where he has gone down, but also fouls and penalties that should have been given but were not."
Adriano also claimed his team-mate was a better player than Real Madrid's world record signing Gareth Bale.
He said: "His achievements in football - playing a starring role in Confederations Cup and Copa Libertadores-winning sides - make him a better player than Bale.
"Neymar is ahead of Bale, for what he has done in football, for what he is in Brazil and for what he is doing at Barca.
"Bale has yet to emulate Neymar on football's biggest stages. Neymar is already a world star."