The ruling from the Court of Arbitration for Sport (CAS) in Lausanne on Friday upheld FIFA's ban with the stinging remark that "the sanction is relatively mild given the seriousness of the offence."
In a statement FIFA, world football's governing body, said it was "satisfied" by the decision and re-confirmed its policy of zero tolerance to corruption.
Adamu was banned by FIFA's ethics committee last year following a Sunday Times investigation when he was secretly filmed by journalists, posing as lobbyists, asking for $800,000 to influence his vote in the 2018 World Cup bidding process.
CAS said in its ruling: "The CAS panel stressed that it was of crucial importance that top football officials should not only be honest but should evidently and undoubtedly be seen to be honest.
"With respect to the behaviour of Dr Adamu, the CAS panel was comfortably satisfied that he was far from actively and unambiguously refusing the improper offer set forth by the alleged lobbyists.
"In conclusion, the CAS arbitrators considered that the sanction imposed by FIFA was not disproportionate and was even relatively mild given the seriousness of the offence."
FIFA said in its statement that it had taken note of the CAS decision and that the decision "further underlines FIFA's zero tolerance and clear stance against any breach of the FIFA Code of Ethics."
CAS will rule in April regarding an appeal by Mohamed Bin Hammam of Qatar, another former FIFA member banned for life last year for bribery.
He has also appealed to CAS and that hearing will take place on April 18/19.
