Being deceived means (willfully) believing a lie and the father of lies, murdering truth (John 8:42-44).
The lie was?
The same kind of lie Satan created for himself.
Eat this fruit, and you will be wise as God! Genesis 3:4
ADAM knew better. He was not deceived.
He was there with the woman and knew what the serpent had said.
Interestingly, the Hebrew says, Adam munched the fruit down quite aggressively.
Why?
Adam reacted to the pressure of the lie when he sinned, because he saw the Lord as not being able to keep the confusion away.
In essence, Adam in his mind possibly joined the enemy, so the enemy would stop bothering him. So, he could then become his own God after the fruit made him able to be.
It is the same kind of sin that many of us face. In frustration, knowing better. We go ahead and do a wrong thing in reaction and anger!
I do not claim to have the answer to all this.
What I said is what I have learned from study over the years.
I believe Adam hated the pressure of having an enemy, and wanted it all to end. He refused to obey the Lord's command in
the pressure, and ended up with having from then on, the constant pressure of needing to discern good from evil to keep on living.
How many of us wish it would just end and be over with?
Welcome to the world of Adam.
grace and peace!