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: If the skin is painful, seek medical attention. 
Sentence2: If your skin hurts, your touch receptors will sense differences.
Example Output: skin

Example Input: Sentence1: Dilation occurs when cell walls relax. 
Sentence2: Decreased oxygen levels cause blood vessels to dilate and cell walls to relax.
Example Output: relax

Example Input: Sentence1: Animals adapt to cold temperatures. 
Sentence2: Cold wet weather, even without freezing temperatures can cause hypothermia.
Example Output:
temperatures