The most common and most likely answer to this crossword clue is the 4 letter word SURF
I've seen this crossword clue in The Guardian
S
U
R
F
More clues leading to the result SURF
- Reportedly one who was bound to explore the internet
- Waves one off from plane
- Breakers from Soviet Union’s Russian Federation leaders
- Get on board to hop Channel rapidly
- Mostly confident fellow is to spend time on-line
- Fail to stick with one channel sea feature
- Ride a white horse?
- Waves certainly moving trailing character on?
- Sounds like one bound for the crest of a wave
- Randomly look at small core of labour force?
Buddy explains!

The straight part
We know that "Fail to stick with one channel/sea feature" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fail to stick with one channel/sea feature = surf.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 SURF mean?
SURF noun- Waves that break on an ocean shoreline.
- An instance or session of riding a surfboard in the surf.
- The bottom of a drain.
- To ride a wave, usually on a surfboard.
- To browse the Internet, television, etc.