As a verb (ithyl, ithylled, ithylling), it means "to interpret that/this however you'd like". Can be used as a command. In its intransitive form ("Sally took a moment to ithyl."), the object of interpretation is assumed to be the person's given situation, or whatever object of interest is being spoken of at the moment. This verb is distinguished from the verb "interpret" by virtue of implying a deliberate disregard for any intentions behind the creation of whatever is being interpreted.
As a noun (ithyl, ithyls), refers to something done or created with a deliberately ambiguous or vague intention or message, for the purpose of encouraging someone else to come up with their own individual interpretation of it.
Possible adjective forms of the word (if you absolutely must use them): ithyllic, ithylly, ithylesque, ithyl-like.
"In chapter four of your book, why did you abruptly change the personality of the main character?"
"Good question. I'd rather you ithyl than get an answer from me."
"When I ithylled the artist's new painting, I arrived at a conclusion that was the opposite of what she intended. I like mine better."
"In my spare time, I doodle little ithyls on napkins and leave them around libraries for strangers to find."