TRICK-OR-TREAT!

One can wonder how to sign “Trick or treat!” in American Sign Language (ASL). In fact, there are many ways to do it.

One way is to sign FOOL followed by CANDY. One can also combine the sign for KNOCKING with OPENING A BAG, or use the sign for TEASING along with a gesture meaning GIVE TO ME.

Indeed, there are many different versions of "trick or treat" even in ASL dictionaries. Furthermore, it is also good to note that while the English phrase includes the word "or," ASL does not require signing the conjunction.

As for signing costume, given the context of Halloween, simply using the signing CLOTHES is okay and will be understood as costume. The context itself fills in the meaning. Yet, if one wants to be clear and specific, they can sign CLOTHES after signing HALLOWEEN.

Thus, for ASL conversation where the context significantly shapes the meaning, simply memorizing a one-to-one corresponding sign to an English word is not enough. 

Indeed, signs can vary across the region, generation, or community. So, if you meet any Deaf friends or neighbors this Halloween, try observing the signs they use, rather than treating any single sign as the definitive correct answer. 

Happy Halloween!