As nouns the difference between drain and headwall

is that drain is a conduit allowing liquid to flow out of an otherwise contained volume while headwall is (geography) the highest cliff of a glacial cirque.

As a verb drain

is to lose liquid.

As nouns the difference between culvert and headwall

is that culvert is a transverse channel under a road or railway for the draining of water while headwall is the highest cliff of a glacial cirque.

As a verb culvert

is to channel (a stream of water) through a culvert.

As a noun cavity

is a hole or hollow depression.

As an adjective cavityless is

without a cavity or cavities.

As nouns the difference between event and fanfest

is that event is blowhole (of cetaceans) while fanfest is an event held for fans.

As nouns the difference between fan and fanfest

is that fan is a hand-held device consisting of concertinaed material, or slats of material, gathered together at one end, that may be opened out into the shape of a sector of a circle and waved back and forth in order to move air towards oneself and cool oneself while fanfest is an event held for fans.

As a verb fan

is to blow air on (something) by means of a fan (hand-held, mechanical or electrical) or otherwise.

As a proper noun Fan

is a diminutive of Frances.

As an abbreviation FAN

is file area network.

As an adjective fearsome

is frightening, especially in appearance.

As a noun fearsomeness is

the state or condition of being fearsome.

As nouns the difference between cliff and headwall

is that cliff is a vertical (or nearly vertical) rock face while headwall is the highest cliff of a glacial cirque.

As a proper noun Cliff

is a diminutive of the male given name Clifford.

In geology terms the difference between glacial and headwall

is that glacial is of the Pleistocene period dominated by the presence of glaciers while headwall is the steep cliff at the back of a cirque.

As an adjective glacial

is of, or relating to glaciers.

As a proper noun Glacial

is of the Pleistocene period dominated by the presence of glaciers.

As a noun headwall is

the highest cliff of a glacial cirque.

As nouns the difference between spoonerism and marrowsky

is that spoonerism is a play on words on a phrase in which the initial (usually consonantal) sounds of two or more of the main words are transposed while marrowsky is spoonerism.

As a noun conversation

is conversation.

As an adjective conversationless is

without conversation.