The word pervasive comes from the Latin.  The English adjective was formed by combining the past participle stem pervās- (from pervādere) (meaning "to go through" or "spread through") with the English suffix -ive ("tending to", "having the nature of" or "relating to").  It describes something that spreads throughout or permeates everywhere, and it's often used to describe "odors", "ideas", or "influences".  

According to the Oxford English Dictionary (OED), the earliest known use of the adjective "pervasive" in English is from 1736, and the citation comes from the writings of Aaron Hill, a writer and entrepreneur.  The word was formed by adding the suffix "-ive" to the Latin past participle stem pervas- of the verb pervadere, meaning "to spread or go through". 

Examples of "pervasive" used in a sentence: 
"It's a pervasive attitude that goes well beyond politicians."
"The smell of garlic is a pervasive presence in my house when my wife is making sauce." 
"And while the nursery is clean and filled with caring staff, there is a pervasive sense of sadness." 
"Although his own career faded, his influence remained pervasive in the work of other performers." 
"There was a pervasive feeling among the staff that none of the hospital administrators cared about their problems."
"The teachers on the second floor were complaining about the pervasive smell of sulfur coming from the chemistry classroom." 

Just the facts:

PERVASIVE Definition & Meaning - Merriam-Webster

PERVASIVE Synonyms: 49 Similar and Opposite Words | Merriam-Webster Thesaurus

Appeals for money from worthy causes have become so pervasive that many have developed what might be termed "giver's irritation" when ANY such appeal is made.