The Football Association will take no action against a Fleetwood Town employee for a comment towards Wycombe Wanderers striker Adebayo Akinfenwa.
Akinfenwa alleged he was called a "buffalo" during their League One play-off semi-final second leg in July.
No complaint was made to officials during or after the game, but a formal complaint was later made to the FA.
The FA spoke to witnesses and an independent expert but did not have "sufficient evidence" to charge.
The Professional Footballers' Association says it is "disappointed" that the FA will not charge the Fleetwood representative, adding that they "share Adebayo's disappointment that this allegation will not be upheld".
"It is abundantly clear that a white player with a similar stature to Akinfenwa would never be described in the way he was during this incident," the PFA said in a statement.
"Black people have battled dehumanisation for centuries, and the PFA strongly condemns the use of all disparaging remarks that compare black players to animals."
Akinfenwa, 38, alleged a Fleetwood representative had called him a "fat water buffalo", with accounts from both clubs' players and staff, and two match officials, confirming use of the term "water buffalo" or "buffalo".
Akinfenwa had said it "dehumanises me as a black man by associating me to a water buffalo, a dark animal, in a derogatory manner".
But there was a difference in opinion over whether the term was discriminatory in either nature or context, with neither match official interpreting the words in that manner.
The Fleetwood member accepted using the words but denied they were used in a discriminatory context, saying they were used to "describe the player's actions".
The FA commissioned a report from an independent expert in race relations, which concluded the words were not "objectively racist" and therefore concluded there was insufficient evidence to put before a regulatory commission.
"Whilst on this occasion the words have not been deemed to be discriminatory, the FA understands the offence that has been caused to the Wycombe player by their use," said an FA statement.
"The FA will therefore seek to monitor the use of these words moving forwards and discourage their use given the potential they have to offend."
Wycombe, who went on to win the play-offs, said in a statement: "The club disagrees with the conclusion of the Football Association. The investigation confirms that the language was used. There is no place in sport for such comments.
"The club believes the FA had the opportunity to take appropriate steps to ensure the conduct was punished appropriately and to make sure that everyone knows that this type of comment will not be tolerated in the future. The failure of the FA to act is disappointing."
In their own statement, Fleetwood added: "The club have co-operated fully in regards to the matter and welcome the decision of the FA and in particular the independent expert's conclusion that the employee's comments were not objectively racist.
"As a club we operate a no tolerance approach in regards to discrimination of all kinds and continue to support the EFL's Not Today or Any Day campaign which encourages behavioural and attitude changes at all levels of football."