Pronunciation: [swˈɛl ˈʌp] (IPA) 
The spelling of the phrase "swell up" is quite straightforward. The word "swell" is spelled with a double "l" and a silent "w", as in /swɛl/. The addition of the particle "up" is simply spelled as it sounds, /ʌp/. When pronounced together, "swell up" is pronounced as /swɛl ʌp/. This idiomatic expression refers to an expansion in size or volume, typically used to describe swelling after an injury or inflammation.
The phrase "swell up" refers to the action or process of experiencing an abnormal or excessive enlargement or increase in size, volume, or mass. It is commonly used in both literal and figurative contexts. In a literal sense, "swell up" can describe when a body part or area of the body becomes inflamed, engorged, or puffy due to injury, infection, allergic reaction, or other medical condition. For example, if someone sustains a bee sting, their affected skin may swell up as a result of the body's immune response.
In a figurative sense, "swell up" can describe a psychological or emotional reaction characterized by an intense rise in emotions or feelings. This can occur due to excitement, pride, anger, or grief, among other reasons. For instance, if someone receives unexpected good news, their heart may swell up with joy or happiness. Additionally, the phrase can be used to indicate an increase or expansion in ego, arrogance, or self-importance, often associated with feelings of superiority or inflated self-worth.
Overall, "swell up" encompasses the concept of enlargement, whether physical or emotional, and portrays a state of heightened intensity, either positive or negative, within an individual or in relation to their surroundings.
The etymology of the phrase "swell up" can be traced back to Middle English. The word "swell" originated from Old English "swellan", which meant "to grow, to increase in size or force". The term "up" is a simple adverb indicating direction or completion. When combined, "swell up" came to describe the action of something, such as a body part, becoming larger or inflamed due to various factors like injury, infection, or allergic reaction. Over time, it has become a commonly used phrase in English to express the process of swelling or the state of being swollen.
