What is the meaning of the noble verse: "But do not make a secret appointment with them, unless you speak a recognized word," and based on it, is it permissible for a man and a woman to meet in secret without their families' knowledge, if they are speaking a recognized word?

It is permissible to allude to proposing to a woman whose husband has died, during her iddah (definition) (waiting period), without making an explicit proposal. Examples include the suitor saying: "I wish to marry, and I like a woman of such-and-such qualities," or "I wish Allah would bless me with a wife." However, it is forbidden to explicitly propose or to secretly promise to marry her, such as by saying: "I am in love, promise me you won't marry anyone else," or "Don't let me miss out on you, for I will marry you." This is because proposing to a woman observing iddah for a deceased husband is prohibited.