While we know that we have some suffixes in ASL, such as -ER. E.g. TEACH+PERSON in ASL for "teacher" in ASL.
While it appears that there is little research on prefixes in ASL. Based on my observation of everyday conversations in sign language, the ASL prefix "REAL+[WORD] seems to be the case. Delete the movement, only index finger onto the chin + [WORD].
Search/Filter: Enter a keyword in the filter/search box to see a list of available words with the "All" selection. Click on the page number if needed. Click on the blue link to look up the word. For best result, enter a partial word to see variations of the word.
Alphabetical letters: It's useful for 1) a single-letter word (such as A, B, etc.) and 2) very short words (e.g. "to", "he", etc.) to narrow down the words and pages in the list.
For best result, enter a short word in the search box, then select the alphetical letter (and page number if needed), and click on the blue link.
Don't forget to click "All" back when you search another word with a different initial letter.
If you cannot find (perhaps overlook) a word but you can still see a list of links, then keep looking until the links disappear! Sharpening your eye or maybe refine your alphabetical index skill. :)
Add a Word: This dictionary is not exhaustive; ASL signs are constantly added to the dictionary. If you don't find a word/sign, you can send your request (only if a single link doesn't show in the result).
Videos: The first video may be NOT the answer you're looking for. There are several signs for different meanings, contexts, and/or variations. Browsing all the way down to the next search box is highly recommended.
Video speed: Signing too fast in the videos? See HELP in the footer.
ASL has its own grammar and structure in sentences that works differently from English. For plurals, verb inflections, word order, etc., learn grammar in the "ASL Learn" section. For search in the dictionary, use the present-time verbs and base words. If you look for "said", look up the word "say". Likewise, if you look for an adjective word, try the noun or vice versa. E.g. The ASL signs for French and France are the same. If you look for a plural word, use a singular word.