The most common and most likely answer to this crossword clue is the 7 letter word HUMMERS
H
U
M
M
E
R
S
Buddy explains!
The straight part
We know that "who don’t know the lines" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case who don’t know the lines = hummers.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 HUMMERS mean?
HUMMERS noun- One who hums.
- A Humvee.
- A type of vehicle resembling a jeep but bulkier.
- A hummingbird.
- A humdinger.
- A fastball.
- Fellatio in which the person performing the act vibrates their mouth by humming.
- A very energetic or lively person, a powerful lively thing.
- Something or someone exceptional of their type.
- An obvious lie.
- A liar.
- An erection of the penis.
- An arrest on false pretexts.