Of course, they mean she is interested in you... okay maybe it's a platonic interest but I would say that's highly unlikely, there's probably no such thing... but don't go getting excited, she probably hands these looks out to 1/4 of the guys she meets, so what it means is you have a chance, only a chance, that if you play your cards right she may eventually be DTF.
However, if she is married that changes the game a bit. You must close on first hangout before her logical brain kicks in amd tells her it's wrong and shuts you down... and a "insta date" type scenario is more likely than a formal date. That is yoy must come in under the radar, build attraction and then capitalize all in one go, then after she will feel significant buyers' remorse, feel terribly guilty, probably hate you too... this is why it might be a bad plan if she's a colleague.
Unless... well there are a lot of bored and unhappy women out there many of whom are stuck in loveless relationships, especially if they have kids... so, suss out the situation, you might be doing her (and him) an enormous favour. In my experience if she's in this category she'll allude to it sooner or later, then you just ask "do you love him?" and proceed on that basis.
For instance my current GF is in this category (bored and frustrated, wants to make her marriage work but doesn't know how to do so and feels it is out of her hands)... OTOH had a major crush on my JP teacher for like a year, eventually were discussing her life and relationship which are both pretty boring, she sadly told me he won't "put a ring on it", I replied "ai shiteru kedo?" -- but do you love him (wholeheartedly)? And she replied just as sadly that she does... so I've left her alone since then, & I don't really get out the sexual flirting as much...
-Ray