FALINGO : to lose , to disappear, to be missing.
Dies libras ha na' falingo! S/he lost ten pounds!
Håfa malingu-mo? What did you lose?
Dångkulo i malingu-ho. I lost a lot.
Malingo i salåppe'. The money disappeared.
Malingo means "lost" as in "not found," or "not visible to the one seeking."
Abak means to lose one's way; to not know where one is or how to proceed or return.
"Malingo i patgon" means that a child is lost and, up to now, has not been found.
"Abak i patgon" means that a child doesn't know where s/he is and how to get home.
In the Chamorro hymn about the Child Jesus lost in the Temple, part of it goes :
Tayuyute ham, Maria, gi patgon-mo ni malingo.
(Pray for us, Mary, to your child who went missing.)
Our Lord was not abak; He knew exactly where He was. But He was missing, lost to Mary who didn't know for three days where He was.
As a side note, petdido is a Spanish word meaning "lost" and is used in the title for Jesus when He was lost in the Temple. Niño Perdido means "Lost Child" and is the patron of Asan's Church.
But, among older Chamorros, petdido is also used to mean "lost" but in a very negative way. It implies a hopeless, irredeemable loss.
"Mångge i salape'-mo?" (Where is your money?)
"Petdido." (Lost, as in a bet, and can never return.)
When speaking about someone who is seen as a hopeless alcoholic, drug addict or always in trouble with the law, older people will sometimes say that person is petdido.
This sense, of course, is not applied to the Lost Child Jesus.