Luk 9:25 For what is a man advantaged, if he gain the whole world, and lose himself, or be cast away?
Since what is going to be helped, a person gaining the world order, all of it, himself, however, destroying or being damaged.
In this verse, the references is to the "self", where, in the previous verse, it was to "self-awareness". The Matthew version uses the Greek "soul", which is the same as the word translated as "life" in the previous verse and meaning "awareness".
The word translated as "what" can also be translated as "who," or "how." However, it usually acts as a question word in short phrases, not long sentences.
The word translated as "is advantaged"means being helped or aided. In the Matthew version of this verse, it is translated as "profit".
The word translated as "gain" means, interestingly enough, to gain in the sense of gain an advantage and, interestingly enough, "to derive a profit." But in a phrase like this, we would normally say "win over." It is an adjective, "gaining".
The word translated as "world" doesn't mean the planet, but the idea, especially as Christ uses it, is more like we use the word "society," that is, the world of men, its power structures, and its values. More about this word and related words in this article.
The word translated as "lose" means to "destroy" or "demolish". It is in the form of an adjective, "destroying> It is not the same verb translated as "lose" in the Matthew version, which is the verb below.
"Himself" is a reflexive pronoun that means "self". In the previous verse, it was used with "awareness" to clarify the idea of "self-awareness".
The word translated as "cast away" means "to damage", "to cause a loss" or "to penalize". It is passive, describing something that might happen. It is also in the form of an adjective, a passive one, "being damaged." It is not the word usually translated as "cast away" in the Gospels.
κερδήσας (part sg aor act masc nom) "Gain" is from kerdainô, which means "to gain", "to derive profit", "to spare or save oneself," and to "gain an advantage." In a negative sense, it means "to reap a disadvantage from a thing."
δὲ "But" is from de (de), which means "but" and "on the other hand." It is the particle that joins sentences in an adversarial way but can also be a weak connective ("and") and explanation of cause ("so") and a condition ("if").
ζημιωθείς; (part sg aor pass masc nom) "Lose" is from zêmioô, which means "to damage", "to cause loss", "to fine," and "to penalize." In the passive form it means "to be fined," and "to suffer a financial loss."