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: Contact with infected blood, contaminated needles. 
Sentence2: scraping oneself on an infected needle may cause infection.
Example Output: infected

Example Input: Sentence1: Ferns are vascular plants. 
Sentence2: when a fern grows, its size of leaves may increase.
Example Output: Ferns

Example Input: Sentence1: Any act of consuming is referred to as eating. 
Sentence2: Heterotrophs get food by consuming other living things.
Example Output:
consuming