(/ˈfɜːtɪv/)
Adverb
1. Exhibiting guilty or evasive secrecy.
2. Stealthy.
… INTERIOR RALPH’S
It is late, the supermarket all but deserted. We are tracking in on a fortyish man in Bermuda shorts and sunglasses at the dairy case. He is the Dude. His rumpled look and relaxed manner suggest a man in whom casualness runs deep. He is feeling quarts of milk for coldness and examining their expiration dates. The Dude glances furtively about and then opens a quart of milk. He sticks his nose in the spout and sniffs.
From the post: English Vocabulary from the movie “The Big Lebowski”
Source: Big Lebowski, The Script at IMSDb. (imsdb.com)