There are 21 words that start with 'rous'.
| rouse | roust | roused | 
| rouser | rouses | rousts | 
| rousers | rousing | rousted | 
| rouster | rousseau | rousters | 
| rousting | rousement | rousingly | 
| rousseaus | rouseabout | rousements | 
| roustabout | rouseabouts | roustabouts | 
Note: These 21 words that start with 'rous' are found from the USA & Canada version of the tournament Scrabble word list.