For all time, for all eternity; for a lifetime; for an infinite amount of time.
“I shall love you forever.”
For a very long time, a seeming eternity.
“We had to wait forever to get inside.”
Constantly or frequently.
“You are forever nagging me.”
An extremely long time.
“I haven’t seen him in forever!”
a mythical time in the infinite future that will never come.
“Sure, I’d be happy to meet with you on the 12th of forever.”
In a manner that is not definite.
“an indefinitely determined fossil”
For a long time, with no defined end.
for an unlimited or unspecified period of time
“talks cannot go on indefinitely”
to an unlimited or unspecified degree or extent
“an indefinitely large number of channels”