Essential Condition
Requisite, Must
noun
You already learned that 必須 can mean "essential" and that 条件 means "condition," so put them together and you get essential condition! That basically means that it's a must.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
お肌の張りと艶は、モテる女の必須条件です。
Shiny, toned skin is a must for popular women.