This sign at OG says:
Now, I used to think that the word “apparel” had no legitimate plural form, but it appears I was wrong.
Google’s dictionary says:
However, I don’t think Pierre Cardin is offering 20% off embroidered ornamentation on ecclesiastical vestments. I think they’re offering 20% off men’s shirts.
I was wrong, yes, but the sign was also wrong, unless “apparels” is a verb, and the sign is really saying that someone named Pierre Cardin is in the habit of appareling or clothing others… which, in a sense, he is, I suppose.
Below is an example of writing that uses the word “apparels” in the technically correct sense. Note that the plural does not refer to the ecclesiastical vestments or articles of clothing themselves, only to some bits of decoration on them.
While embroidered pieces known as apparels were used on albs, dalmatics, and tunicles to represent Christ’s stigmata when placed at the end of sleeves and at hems, the practice of incorporating this form of ornamentation on vestments was gradually replaced by the use of lace in Western vestments during the sixteenth century.
—Encyclopedia of Clothing and Fashion
So unless you are knowledgeable about albs, dalmatics, and tunicles, steer clear of the word “apparels”.