Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Example Input: Sentence1: Weather today is said to be sunny and clear. 
Sentence2: High pressure systems cause it to be sunny.
Example Output: sunny

Example Input: Sentence1: soil is formed by weathering. 
Sentence2: Something described as loamy is formed by weathering.
Example Output: formed

Example Input: Sentence1: microorganisms can cause infections. 
Sentence2: Infection can cause a range of illnesses.
Example Output:
infections