Effie is the Scottish and English diminutive of Euphemia — from the Greek eu (good) and phēmē (speech, fame) — meaning "well-spoken" or "fair fame."
Effie Brown (American film producer) and Effie Gray (the Victorian-era figure painted by Millais) are notable bearers.
Effie does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Effie reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.