The most common and most likely answer to this crossword clue is the 7 letter word ACRONYM
I've seen this crossword clue in Financial Times
A
C
R
O
N
Y
M
More clues leading to the result ACRONYM
- A close friend beginning to mistrust NATO, for example
- A friend, married, gets pronounceable initials
- Type of word a close friend initially misused
- American with friend in NATO, for example
- Perhaps NATO Member after American ally
- A rumour about ready money getting 17?
- A chum married Nimby, for one
- Initial combination that’s familiar in a mass
- An associate member of Nato, perhaps
- 2 with friend in Nasa?
Buddy explains!
The straight part
We know that "Nasa?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case nasa? = acronym.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 ACRONYM mean?
ACRONYM noun- An abbreviation formed by the initial letters of other words, sometimes exclusively such abbreviations when pronounced as a word (as "laser") rather than as individual letters (initialisms such as "TNT").
- An abbreviation formed by the beginning letters or syllables of other words (as "Benelux").
- To form into an acronym.