Akinaichuu/Open for Business Pun

Here’s how our TL for the OP/ED explains it:
[28/11 22:37:56] I don’t think I have ever seen Arashi 2 subtitle joke explained
[28/11 22:38:19] It’s actually written 春夏冬中 with given reading “akinai chuu”
[28/11 22:38:29] first three kanji are “spring”, “summer” and “winter”
[28/11 22:38:31] with no autumn
[28/11 22:38:35] autumn would be “aki”
[28/11 22:38:40] no autumn = “aki nai”
[28/11 22:38:49] akinai means “business”, obviously