Both Uses of

vigilant

in

Don Quixote

But you must not suppose, because Marcela chose a life of such liberty and independence, and of so little or rather no retirement, that she has given any occasion, or even the semblance of one, for disparagement of her purity and modesty; on the contrary, such and so great is the vigilance with which she watches over her honour, that of all those that court and woo her not one has boasted, or can with truth boast, that she has given him any hope however small of obtaining his desire.†
Chpt 1.11-12 *

vigilance = careful watch

Of a truth I know not; Lothario alone was such a one, for with the utmost care and vigilance he watched over the honour of his friend, and strove to diminish, cut down, and reduce the number of days for going to his house according to their agreement, lest the visits of a young man, wealthy, high-born, and with the attractions he was conscious of possessing, at the house of a woman so beautiful as Camilla, should be regarded with suspicion by the inquisitive and malicious eyes of the idle public.†
Chpt 1.33-34

Definition:

carefully observant or attentive -- often to possible danger