The most common and most likely answer to this crossword clue is the 15 letter word STRAIGHTFORWARD
I've seen this crossword clue in Independent
S
T
R
A
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G
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F
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More clues leading to the result STRAIGHTFORWARD
- Where is very ill patient heading? That's easy
- Open lock possibly underhand?
- Easy for Frank
- Vocal passage, alternatively in F minor, is easy
- Plain sailing? Right on!
- Immediately getting 1 of 19 for Frank
- Even leading may be child’s play
- A piece of cake in hand to be given to dependant
- Just a footballer playing the game
- Routine resettlements of software rights drag endlessly
Buddy explains!

The straight part
We know that "easy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case easy = straightforward.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 STRAIGHTFORWARD mean?
STRAIGHTFORWARD adjective- Proceeding in a straight course or manner; not deviating.
- Easy, simple, without difficulty
- Direct; honest; frank
- In a straightforward manner; straightforwards; straightforwardly.