The most common and most likely answer to this crossword clue is the 7 letter word NIGHTLY
I've seen this crossword clue in The Sunday Telegraph
N
I
G
H
T
L
Y
More clues leading to the result NIGHTLY
- Very often chivalrous to doff cap
- English actress on the radio every evening
- Regularly late, yet sounding chivalrous
- Often heroic, opener dismissed
- Doffing cap, gallant on frequent occasions
- How stars appear chivalrous in audition
- Periodically close account missing a line
- Close telly, oddly, as latest programmes are shown
- Oddly deficient ending that play gives us when it’s performed?
- Every evening, almost, Cobb takes left
Buddy explains!

The straight part
We know that "Often" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case often = nightly.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 NIGHTLY mean?
NIGHTLY adjective- Happening or appearing in the night; night-time; nocturnal.
- Performing, occurring, or taking place every night.
- Used in the night.
- A build of a software program with the latest changes, released every night.
- Every night.