Hi Kate
I work with a lot of eCommerce companies and when a category is essentially in limbo - between seasons where stock may be re-bought then I keep it live. To simply redirect to another unrelated page is not, in my opinion the best result for the customer.
If a customer is searching for Levis (just an example) and you don't have any then why would he want to end up on a generic Jeans page or another brand? The best result is that they see you are out of stock. You could even just put a message on that page saying - Sold Out - stock arriving soon or something like that. (Get the buying plans off the buyers! - they know what is on order for the next 6-9 months!)
The page will remain and get repopulated once stock arrives. If the category is simply out of stock never to return then I would consider redirecting to a higher category - but if it was a brand I may still leave the page as being sold out. (The alternative here is to allow it to 404 so the page disappears all together from SERPs - but then style your 404 page so that they can follow a menu of alternatives).
The last thing you want is a potential customer going round in circles trying to find the brand because you have redirect them somewhere else. So a message like 'We are out of stock of Levis right now but check out these other awesome brands - with a menu' is perfectly fine and a better User Experience (UX)
By creating the best UX you are far more likely to please your buyers and frankly a few pages of skinny content is not going to kill you in SERPS - you have a perfectly valid reason.
Watch Rand's video on alternative methods but I would do this.
Regards
Nigel