When it comes to business and finance, "cold sectors" refer to those parts of the economy that are not performing well. If you're looking for synonyms for this term, there are a few options to consider. "Underperforming sectors" is a common phrase used to describe industries that are struggling. You could also use "lagging sectors" or "struggling sectors" to convey the same idea. Alternatively, "sluggish sectors" could work if you want to emphasize a lack of momentum. Regardless of the term you choose, it's important to remember that this language can have an impact on perception, so use it thoughtfully and accurately.