Mine is COSY it's an adjective
It gives a feeling of comfort, warmth, relaxation and it attracts you to a situation.
"You look so cosy sitting in front of the fire reading your book"
"It was raining as I was walking home, as I past a house I looked in & saw the family sitting at the table having dinner. It looked so cosy I just wanted to knock on the door & join them at the table"
I chose "Cosy" as whenever I hear it or say it it makes me feel warm & comfortable.
Why don't you add your favourite word in the comments & put it in a sentence or two to help others improve their vocabulary.