Human-ish

Human-ish was a term used to unfavourably describe people who were genetically close to humans. Like the Tylerkind, who had genetically adapted to life on the mostly-aquatic Tyler's Folly, human-ish people had slightly different, and undesirable, physiologies from the human baseline. According to Kommander Ernst Katastrophen and others, the word subhuman was a synonym. (PROSE: Down) Equally, at a much later period in history, Lady Cassandra, who claimed to be "the last human", spoke as if humans were superior to the "human-ish". (TV: The End of the World)

Thus, unlike the term humanoid, human-ish was flatly derogatory. Indeed, the measurement of "human-ish-ness" was used in at least the 26th century as a means of racial suppression by the SSSSSSS. In the middle of the century, legislation by the name of the First Demographic Charter of 2537 arose which gave both power and definition to the measurement of a person's level of humanity. Bernice Summerfield found the SSSSSSS' efforts at genetic management on Tyler's Folly both laughable and worthy of her opposition. (PROSE: Down)

In the year 5,000,000,000, the Ninth Doctor and Rose Tyler listened while Lady Cassandra flatly implied that true humans were superior to the human-ish. Though genetics were a part of the way Cassandra vaguely defined the word, the term had at least a somewhat meaning for her, as she associated "true humanity" with having been born on Earth. (TV: The End of the World)

Behind the scenes
Technically, only the narrator of Down uses the term human-ish, allowing the SSSSSSS characters to use the more blatantly racist subhuman. However, the term does appear in dialogue in The End of the World. Hence, from the book, we derive the hyphenated spelling and from the episode comes the fact that the term is definitely known by average characters in the DWU.