The most common and most likely answer to this crossword clue is the 6 letter word FASTEN
F
A
S
T
E
N
More clues leading to the result FASTEN
- Fan outside set, somehow, for tie
- Speedy dash to make secure
- Very little gun clip?
- Lot keeping south and north secure
- Secure a way through marshland
- Football Association’s slightly deficient team in tie
- Quick points resulting in tie
- In flat marshy land, a drained settlement is secure
- Join footballers setting up equipment for goals
- Bolt‘s very quick and keen on a regular basis
Buddy explains!

The straight part
We know that "secure" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case secure = fasten.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 FASTEN mean?
FASTEN verb- To attach or connect in a secure manner.
- To cause to take close effect; to make to tell; to land.