If something is provided without a charge or payment, then it is free. If it is offered as a gift or courtesy, it is complimentary. Politeness is at the heart of this adjective, which also means “expressing a compliment, often one that is politely flattering.” Politeness or courtesy is also at the heart of the hospitality industry, where one is likely to encounter complimentary items, such as a complimentary breakfast or complimentary Wi-Fi. Forgoing a few syllables, a particularly lucky hotel guest might also experience a meal or service being comped, or provided free of charge.
The verb finalize is close in meaning to the verb complete—both deal with finishing something. But complete is more likely to be used in discussion of tasks or steps, such as completing a job application or an essay for school. Finalize occurs more in discussion of protracted engagements, such as long business negotiations or a divorce. Note that finalize draws the ire of some stylists, along with other -ize verbs such as prioritize—so perhaps avoid this term in your next ode or sonnet! But rest assured, dear scribes, finalize is widely used in speech and writing.
To call something absurd is to point out its utter senselessness or foolishness. To call something incongruous is to point that it is out of place or inconsistent. These two adjectives, which emphasize slightly different qualities, overlap when the incongruity or inconsistency under discussion is so pronounced or outlandish that it veers into the absurd or laughable.