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: Results can be damaging or disastrous. 
Sentence2: Lack of immunization can be damaging or disastrous.
Example Output: damaging

Example Input: Sentence1: If there is no movement friction is zero. 
Sentence2: Movement causes the temperature of an object to increase.
Example Output: movement

Example Input: Sentence1: Freshwater biomes have water that contains little or no salt. 
Sentence2: Salinity is the measure of salts in the water.
Example Output:
salt