be, seem
become
The origins of the tradition have become obscure.

remain
The motives behind this decision remain somewhat obscure.

extremely, fairly, very, etc.
completely, totally
largely
relatively
wilfully/willfully (esp. BrE)

Obscure is used with these nouns:
corner, disease, jargon, journal, origin, reference

completely, totally
almost
largely
half, partially, partly, slightly, somewhat
deliberately
All trace of his working-class background was deliberately obscured.

easily
Solo passages in this register are very easily obscured by other instruments.

serve to, tend to
The emphasis on social integration often served to obscure the real differences within the community.

allow sth to

behind
The moon was obscured behind a wall of cloud.

in
The right-hand side of the face is obscured in deep shadow.

obscure the fact that …
These figures obscure the fact that a lot of older people live in poverty.

obscure sth from view
The house was obscured from view by a wall.

Obscure is used with these nouns as the subject:
cloud, fog, mist

Obscure is used with these nouns as the object:
distinction, extent, fact, reality, view, vision