Pronunciation: [wɒst ɪnsˈɛnsd] (IPA) 
The correct spelling of the word is "wroth incensed," not "wast incensed." "Wroth" means extremely angry, and "incensed" means extremely angry or outraged. The correct pronunciation of "wroth" is /rɒθ/ (or "rawth"), and the correct pronunciation of "incensed" is /ɪnˈsɛnst/ (or "in-senst"). It's important to use the correct spelling and pronunciation of words to effectively communicate your thoughts and ideas.
The phrase "wast incensed" does not have a unique etymology as it is actually a combination of two different words: "wast" and "incensed".
The word "wast" is the archaic second-person singular past tense of the verb "be" in Middle English. It was commonly used in early Modern English up until the 17th century before being replaced by "were" in contemporary English. So, "wast" simply means "you were".
On the other hand, "incensed" is derived from the Latin word "incensum", which is the past participle of the verb "incendere", meaning "to set on fire" or "to inflame". The word eventually made its way into Old French as "incens", and then into Middle English as "incensed".
