There are 16 words that start with 'retar'.
| retard | retards | retarded |
| retarder | retarget | retardant |
| retardate | retarders | retarding |
| retargets | retardants | retardates |
| retargeted | retardation | retargeting |
| retardations | ||
Note: These 16 words that start with 'retar' are found from the USA & Canada version of the tournament Scrabble word list.