There are a number of owl swear words and curses in Hoolian. They are ranked here from least to most severe.
"Wet Pooper!" -- An insult as it refers to seagulls, who are considered the worst wet poopers of all. Also used in potty humor.
- "You‘re no better than a bunch of wet poopers!"
- ―Horace Plithiver, The Journey, page 45
"Splat-brained!" -- Another insult used similarly to "wet pooper."
"Great Glaux!" -- Not technically considered a swear word. Used to express surprise. Similar to the phrase "Oh God!"
"Great Glaux in Glaumora!" -- an extended version of "Great Glaux!"
"Ferschtucken" -- A curse word used primarily in the Northern Kingdoms, used as a more offensive version of "God forsaken."
"Frink" -- Mild profanity, used as follows: "That really frinks me off" or "frink off!" Similar to the phrase "that really pisses me off!"
"Racdrops!" -- Short for raccoon droppings. Raccoons are considered an extremely repulsive animal. Used to express great disgust. An analogue of the S word.
"Sprink" -- The absolute worst swear word an owl can utter, i.e. the most extreme profanity. Absolutely forbidden at Ga'Hoole. Dewlap is known to have fainted when Otulissa uttered it in the library, referring to the spronk book. Otulissa also sprinked Dewlap herself after a long Flint mop. An analogue of the F word.
"Glaux blood'' -- The worst curse an owl could say. Used as a phrase to condemn another. It is not specified if it is not as bad, worse, or on the same level as "sprink."