Skeptic and septic are easily confused words. One of these words deals with some biological stuff, so I hope you aren’t eating while reading this.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary, but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted, or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Skeptic (pronounced “skehp-tick”) is a noun. It means someone inclined not trust believe incoming information. The related adjective is skeptical, which describes someone disinclined to believe what he/she sees, reads, or hears.
Septic (pronounced “sehp-tick”) is an adjective.
It describes something related to sepsis or being infected. Sepsis means invaded by microorganisms or toxins. Even in 2017, it is possible to die from sepsis.
It can also refer to something putrefactive, or relating to decay or decomposition. For example, a septic tank is a tank buried in the yard of a home that connects to household plumbing. It handles toilet and other wastewater and must be monitored that all its contents are not overwhelming the tank. Periodically their contents must be vaccummed/suctioned out. Septic tanks are used for homes that are rural, and/or not connected to a city sewer/wastewater system.
The following story uses both words correctly:
Saku was house-sitting in the Ozark mountains, working on her novel, when a knock came at the door. A man was offering to examine the septic system and make sure it was working properly. This had been the second free laborer to come by and offer home-related services without her or the owner’s request. Being an affirmed skeptic, she declined to grant him access to look at anything related to the house.