present participle of absorb
"The crowd became a single, dark mass as they absorbed into the stadium during halftime."
capable of arousing and holding the attention
"a fascinating story"
Engrossing, that sustains someone's interest.
"The detective novel was so absorbing that I couldn't put it down until I found out who committed the crime."
This word comes from the verb absorb combined with the suffix -ing. It originally meant the act of taking in or soaking up something.