This is about a Biblical concept, not an emotion, just to make that clear for anyone who is unfamiliar with the word. The word "rapture" comes from the Latin "rapere" (or other form of the root) meaning "to be snatched away" or "caught up". Our English understanding of it carries the connotation of an emotional experience by which we are "carried away".
The meaning of "rapture" in the Bible is the same but without the emotional connotation. However, discussion of this topic does bring out some very strong emotional responses from people who either disagree about the timing of it or reject it outright. Sometimes, just say you believe in any kind of Rapture regardless of timing, and many people will label you an escapist, or worse.
What the Rapture is all about is an event wherein believers are "caught up" to heaven without having to die. There are two known cases of it in the OT: Enoch and Elijah. But as it is taught in the NT, the Rapture refers to the sudden disappearance of all living believers at the same moment.
The following material is edited from a thread in another message board.
The word "apostasia" is a Greek compound of 'apo,' or 'from' and 'istemi,' or 'stand.' Thus it has the core meaning of 'away from' or 'departure,' 'disappearance.' Gordon Lewis explains how the verb from which the noun 'apostasia' is derived supports the basic meaning of 'departure' in the following:
"The verb may mean to remove spatially. There is little reason then to deny that the noun can mean such a spatial removal or departure. Since the noun is used only one other time in the New Testament, of the apostasy from Moses [Acts 21:21], we can hardly conclude that its Biblical meaning is necessarily determined. The verb is used fifteen times in the New Testament. Of these fifteen, only three have to do with a departure from the faith [Lk.8:13; 1 Tim.4:1; Heb.3:12]. The word is used for departing from iniquity [2 Tim.2:19], from ungodly men [1 Tim.6:5], from the temple [Lk.2:27], from the body [2 Cor.12:8], and from persons [Acts 12:10; Lk.4:13]."
"It is with full assurance of proper exegetical study and with complete confidence in the original languages, that the word meaning of 'apostasia' is defined as 'departure.'" Concludes Daniel Davey.
So the word Rapture comes from the Latin "rapere" which comes from the Greek "apostasia", and all mean "departure".
What precisely does Paul mean when he says that the 'falling away' must come before the tribulation? The definite article 'the' denotes that this will be a definite event, an event distinct from the appearance of the man of sin. The Greek word for 'falling away,' taken by itself, does not mean religious apostasy or defection. Neither does the word mean 'to fall,' as the Greeks have another word for that ['pipto,' I fall; TDI]. The best translation of the word is 'to depart.' The Apostle Paul refers here to a definite event which he calls 'the departure,' and which will occur just before the start of the tribulation. This is the Rapture of the Church.
So the word has core meaning of 'departure' and it depends upon the context to determine whether it is used to mean physical departure or an abstract departure such as a departure from the faith.
The first seven English Bible translations of 'apostasia' all rendered the noun as either 'departure' or 'departing.' They are as follows: Wycliff in AD 1384; Tyndale in AD 1526; Coverdale in AD 1535; Cranmer in AD 1539; Breeches in AD 1576; Beza in AD 1583; and the Geneva in AD 1608.
This supports the notion that the word truly means 'departure.' In fact, Jerome's Latin translation known as the Vulgate in the 4th century renders 'apostasia' with the word 'discessio,' meaning 'departure.' So why did the King James Version depart from the established translation of 'departure?' KJV in AD 1611.
Therefore Beza, the Swiss reformer was the first to transliterate 'apostasia' and create a new word rather than translate it as others had done. The translators of the King James Version were the first to introduce the new rendering of 'apostasia' as 'falling away.' Most English translators have followed the KJV and Beza in departing from translating 'apostasia' as 'departure.' No good reason was ever given.
Therefore, if 2 Thes.2:3 were properly translated per the original text, it should read as follows:
"Let no one in any way deceive you, for it will not come unless the 'departure' comes first, and the man of lawlessness is revealed, the son of perdition." Vs 3.
With that having been stated, the following passages of Scripture are in perfect harmony with the original text in vs 3, using the proper term, 'departure,' instead of 'falling away' or 'apostasy:'
"For the mystery of iniquity does already work; only he who now restrains will continue to restrain until he is taken out of the way." Vs 7.
"And then shall that wicked one be revealed, whom the Lord shall consume with the spirit of His mouth, and shall destroy with the brilliance of His coming." Vs 8.
From the above, we have a much clearer view of the above text referring to the rapture of the Church, when the antichrist will be revealed and when the tribulation will begin. Therefore, the Church will be raptured, then the antichrist will be revealed and the 70th 'Week' of Daniel, the 7 years of tribulation will begin, in Dan.9:27, that blends in perfect harmony with 2 Thes.2:3-8.