I love this! But if you choose words that commonly appear in idioms, you just get the original idiom back. Example:

cat

>cat got your tongue

>cat nap

>curiosity killed the cat

>fight like cat and dog

>grin like a cheshire cat

>let the cat out of the bag

>no room to swing a cat

>not enough room to swing a cat

>not have a cat in hell’s chance

>play cat and mouse