Masculine rhyme refers to any rhyme that matches only a single syllable. Often it’s the final syllable of a word, where that slayable is stressed. An example can be found in John Donne's poem Lecture Upon the Shadow.
Stand still, and I will read to thee
A lecture, love, in Love's philosophy.
This is a good example of masculine rhyme because it only matches the last syllable of each word, and that syllable is stressed. Stressed means that when read aloud the natural emphasis occurs at the end of the word. Masculine rhyme is in contrast to feminine rhyme because it only matches a single syllable and is stressed, as opposed to feminine rhyme, which matches at least two syllables that are unstressed.