Otherwise known as “near rhyme” or “half rhyme.” Unlike perfect rhyme, if two words almost sound alike, then those two words form an “imperfect rhyme.”
Because of the connotation of the word “imperfect,” you may think that it is better to write perfect rhyme. But it is better to use an imperfect rhyme than to sacrifice the idea or tone of your song in order to use a perfect rhyme. Also, sometimes if your song contains too much perfect rhyme, it will sound childish, or too much like a greeting card.
Finally, perfect rhyme is more likely to be cliché because writers have used them so often in past and present times. If you tell me that the first rhyming pair in your new song is “love/run,” I’ll feel better about it than if you tell me it’s “love/dove.” Christian hymnody probably has enough doves of love from above.
Jennie Lee Riddle uses imperfect rhyme in “Revelation Song”:
“Clothed in rainbows of living color
Flashes of lightning, rolls of thunder”
Do you see that “color/thunder” is the imperfect rhyme? The words nearly rhyme because the sound of the “o” in color and “u” in thunder is similar, and also because of an element of imperfect rhyme called consonance (the repetition of the same consonant two or more times in close succession). “Color/thunder” each end with the “r” sound.
Consonance doesn’t have to be present in imperfect rhyme. You can also use assonance, the agreement of vowel sounds within words. “Bright/mine” is assonant because of the long “i” sound. See how Jon Egan uses both assonance and consonance in the first four lines of “I Am Free”:
“Through You the blind will see
Through You the mute will sing
Through You the dead will rise
Through You all hearts will praise”
The words at the end of the first two lines (see/sing) are an example of assonance (the long “e” sound). The words at the end of the next two lines (rise/praise) are an example of consonance (the “s” sound). So, assonance and consonance are each elements of imperfect rhyme.