The phrase "a satisfactory substitute" is correct and usable in written English.
It can be used when discussing an alternative that meets the required standards or expectations in a particular context.
Example: "While the original product was unavailable, the new model proved to be a satisfactory substitute for our needs."
Alternatives: "an acceptable alternative" or "a suitable replacement".
But even Jeremy Paxman thought that "idiot" was not a satisfactory substitute.
It was not just a satisfactory substitute for hitting the road, she said, it was a significant improvement.
A satisfactory substitute in the Brahms -- one of the more challenging works in the repertory -- could not be found.
If further tests should prove that the placental cells are a satisfactory substitute for embryonic stem cells, the company's finding could influence the political debate.
Although the major's latest expansion into 24 teams and 4 6-team divisions was confusing at first, it is a satisfactory substitute for the departed smaller leagues.
In the state's headlong drive to make its psychiatric wards obsolete, officials have publicly maintained for 30 years that the adult homes are a satisfactory substitute.
Mr. Bush has so far refused to lay out his plans with equal precision, and his campaign advertisement saying that nearly 300 prominent economists endorse his general approach is not, in campaign terms, a totally satisfactory substitute for specific details.
billiards-equipment concern had offered a handsome cash prize for the invention of a cheap and satisfactory substitute for ivory billiard balls.
If a player has to leave before a rubber is completed and no satisfactory substitute is available, a side having the only game scores 300 points; a side having the only partscore (trick score of less than 100) in an unfinished game scores 50.
Margarine was invented by the French chemist Hippolyte Mège-Mouriès, who in 1869 won a prize offered by Napoleon III for a satisfactory butter substitute.
Even in a high-tech age when the human capacity to improve upon nature seems limitless, there is no satisfactory substitute for the honeybee.
