The diminished rhyme is in essence an additive rhyme in reverse. The search word's last consonant sound is ignored to create a perfect rhyme with respective mates.
boat > know / although / apropos
gratitude > tissue / aircrew / interview
For dictionary entries with multiple words Rhyme Genie always matches the final word of the phrase. To find only single words simply deselect the phrases, proper nouns and charted songs options.