Similar Sound:
* knock (if you're looking for a similar "ock" sound)
Near Rhymes (Not Perfect):
* stock
* block
* rock
Wordplay (Not Rhymes):
* whitewash (relating to hiding something)
* socialite (playing on the "soc" part)
Context Matters:
The best rhyme depends on the context. For example, if you're writing about a social event, "knock" might work. If you're talking about investment, "stock" would be a better choice.
Let me know if you can give me more information about the context of your rhyme, and I can provide more specific suggestions.