The most common and most likely answer to this crossword clue is the 6 letter word DERIVE
I've seen this crossword clue in The Guardian
D
E
R
I
V
E
More clues leading to the result DERIVE
- Come from Eastern parts to work hard
- Gain enjoyment at first in outing
- Trace of drug found in journey
- Obtain parking place outside house finally
- Take an empty elevator to go down for reception
- Gain from impetus when energy is injected
- Draw of Queen appearing in disreputable club
- Get energy through power
- Get impulse to embrace sweetheart
- Obtain power, energy inside
Buddy explains!

The straight part
We know that "Gain from" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gain from = derive.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DERIVE mean?
DERIVE verb- To obtain or receive (something) from something else.
- To deduce (a conclusion) by reasoning.
- To find the derivation of (a word or phrase).
- To create (a compound) from another by means of a reaction.
- To originate or stem (from).
- To turn the course of (water, etc.); to divert and distribute into subordinate channels.