I hope it's OK to let the cat out of the bag to some extent on 6d
Everyone will have realised that the identical letters in the middle are also the mean.
That results in the original letters being equidistant from that mean, so if all else fails iteratively substitute letters to replace the middle pair.
So if the final entry were, say, "foot", try fnpt/fpnt; fmqt/fqmt..... until a real word emerges