stop·word 
(stŏpwûrd′)
(stŏpwûrd′)n.
A frequently used word, such as a or the, that is not indexed in webpages and thus is not used in search engine queries.
- undecked
- undeclared
- undelete
- undeliverable
- undeliverably
- undemonstrative
- undemonstratively
- undeniable
- undeniably
- undependability
- undependable
- under
- underachieve
- underachievement
- underachiever
- under a cloud
- underact
- underactive
- underactivity
- underage
- underage
- underaged
- underarm
- underbanked
- underbelly