Some terms differ by one or two letters but have a rather distinct or even an opposite meaning. For example:
🦓 osmolarity / osmolality
🦓 absorption / adsorption
🦓 words with hypo- / hyper- prefixes
🦓 words with intra- / -inter- prefixes
🦓 aerobic / anaerobic
🦓 qualitative / quantitative
🦓 dehydro- / dihydro- in chemical names
🦓 ureteroplasty / urethroplasty
🦓 biologic / biological
Have you encountered similar terms in English or another language? You are welcome to continue the list in the comments.
Photo by Neil and Zulma Scott on Unsplash.