The love that dare not speak its name
A reference to homosexual love, although Oscar Wilde denied this in his defense of the charge of gross indecency.
Lord Alfred Douglas coined the phrase in his poem Two Loves, which was printed in the Chameleon in 1896:
"I am the Love that dare not speak its name."
Of course Douglas and Wilde had good reason to be cautious about how they described their relationship - homosexuality was a criminal offence in England in the 19th century.
In April 1895 Wilde was brought to court charged with indecency and sodomy. Charles Gill, a schoolmate of Wilde's and the prosecutor in the case, asked him "What is the love that dare not speak its name?" Wilde's impromptu response was:
"The Love that dare not speak its name" in this century is such a great affection of an elder for a younger man as there was between David and Jonathan, such as Plato made the very basis of his philosophy, and such as you find in the sonnets of Michelangelo and Shakespeare. It is that deep, spiritual affection that is as pure as it is perfect. It dictates and pervades great works of art like those of Shakespeare and Michelangelo, and those two letters of mine, such as they are. It is in this century misunderstood, so much misunderstood that it may be described as the "Love that dare not speak its name," and on account of it I am placed where I am now. It is beautiful, it is fine, it is the noblest form of affection. There is nothing unnatural about it. It is intellectual, and it repeatedly exists between an elder and a younger man, when the elder man has intellect, and the younger man has all the joy, hope and glamour of life before him. That it should be so, the world does not understand. The world mocks at it and sometimes puts one in the pillory for it."
This was well received in court and he was eventually acquitted. Wilde was however later convicted on a second charge and sentenced to two years hard labour.
See also - I have nothing to declare but my genius.