κι ας μην έκαναν τίποτε

[Theseus]

This type of idiom learners like me always find difficult. Here is the context:-
Η Χρυσή και ο Ιάσων που ίσως αγαπούσαν πιο πολύ από τους άλλους τα όμορφα πράματα, τους άρεζε πάντοτε να κάθωνται εκεί μέσα κι ας μην έκαναν τίποτε. Δεν ήταν μόνο ωραία, ήταν όπως έλεγε η Χρυσή τόσο <<φιλική κάμαρα>>.
The passage, incidentally, ends with the group of people, invited by a Mr Laras, asking his piano-loving daughter to play something for them:-
-Παίξε <<ένα πουλάκι την αυγή>> είπε ο Ιάσων
-<<Όχι,>> είπε η Ανδρομάχη· <<Παίξε αυτό που είναι σαν εκκλησία, με τα μεγάλα τα ακόρδα.>>
-<<Παίξε τους αυτό το βαλς που σου έφερε η ματμαζέλ!>>.
-<< Αυτή η κουτή!>> είπε με περιφρόνηση η Ζωή (Mr Laras's pianist daughter).
The first bit I take to mean something like 'to sit there let them not do anything' i.e.'without them doing anything'.
Does the Αυτή η κουτή bit mean 'she is stupid', referring to her piano teacher 'the Madamoiselle ' referred to?

 

[Palavra]

In the first example, the phrase means: "...they liked sitting there, even if doing nothing/even without doing anything".
In the second, the phrase means what you say, i.e.

"Play them that waltz that Mademoiselle brought you."
"Oh, that silly woman!"

Κουτός does mean "stupid", but the register is not the same; it's kind of dated and it reads innocent, even naive, like something that a well-bred () young lady of the '50s would say.

Oh, and note that for Greek quotes you type
Ctrl+Alt+[ for «
and
Ctrl+Alt+] for »

 

[Theseus]

Thanks, Palavra. What a quick reply! I enjoy so much the forum, particularly now I'm convalescing & able to spend quality time on my Greek. I have only got my iPad available: Ctrl + Alt + [ etc. doesn't feature on the keyboard.