Are you referring to your ability to feel engaged by the playing and the music? A lack of inspiration to move beyond your current state, whatever it is, as a player? An existential angst, a 'sameness' to it all that kind of stifles your muse? If so, I think I know what you are talking about. Experienced it early after a few exciting years at the beginning of my so-called playing career. Started strong, hit a wall (probably of my own making), came back many years later, and cursed every moment I spent away. My personal epiphany was the realization that in every endeavor, regardless of how low-brow or high-minded, your biggest gains are always as a beginner, because you go from not having any understanding at all to being functional and dynamic. After that, the desire to keep going, stay engaged, and expand into new levels of comprehension are a matter of personal fortitude. If you don't really wanna, and it's not something you miss when you're away from it, it's only going to reach a particular level and stay there. IMHO, it is more constructive to plod along than it is to resume after completely stopping. You lose all kinds of important intangibles when you lay idle. As a famous baseball manager once said, it's what you learn after you know it all that matters. My advice is to tough it out, keep pushing, and reclaim that mojo. Unless of course, it truly doesn't matter to you and you have made the very personal (and sad) decision that this is the end of the line for you. If this is the case, I have only one more question: What do you have to sell?
Losing your mojo is something that happens to everyone at some point, in any area of life, not just playing bass. If you're not gigging regularly, put the thing away for a couple of weeks and find other things to do. If you are gigging a lot, just do the minimum practice it takes to keep you gig ready, and find other things to do. Or, you could just try doing weird experimental stuff that is totally other than your main style of playing. Mojo can't be forced. It can, however, be made jealous. It'll come back eventually. In an interview, Ian Hill said after a tour, he puts his bass away for a month, then gets it out and starts experimenting.
Quit thinking while you are playing and be a bit cockier while playing. Do that and you should be in good shape.
The opposite of what Byzcat said is what works for me. Work 2X as hard. Learn new stuff. Find a new band to play with. Learn some style or songs outside of what you normally play. Work on an aspect of your playing you don't normally, like performance maybe. Puttin the bass down I would think would just perpetuate tand add to he problem. A new bass always gets my blood going too. Even if it's a cheap one.
New playing situations are usually good for heightening your groove awareness, especially if the new players are very proficient. Nothing like having to make your bones with some hardasses. As someone has pointed out, a change in genre (one you have been meaning to try) can't hurt if you're really intent on getting it. (I s'pose it would be helpful to have proximity to such a band. Another thread, entirely.) Have an exit strategy, whatever. Maybe you'll be led back to your current band. Y'know, I find the toughest aspect of keeping a band fresh is keeping the repertoire moving. It's too easy to settle into a repertoire that doesn't require extensive rehearsal, that everybody knows cold. Picking the new songs can become arduous negotiations because consensus isn't automatic. Don't know if that helps. Either play or don't play. Waffling and grousing definitely kill the muse. Just make a decision. See what happens.
It’s a diabolical plot. There’s a bass player who works for the CIA and he developed a machine that siphons off bass mojo.
Have a go at another instrument to better your understanding of other areas in the band, it helped me appreciate and think of my lines a bit more carefully. Keyboard would probably be safe to suggest here (guitar and I would probably get barred from the forum)
Maybe I'm just thinking that because I'm sidelined with an injured thumb, and I'm getting all these ideas, either spontaneously generated by my brain or from here on TB, on ways to improve my playing. Plus, I get all of my best ideas about just about every aspect of my life while I'm doing something completely unrelated to that particular aspect. I think mileage probably varies a lot.
That's not good advice for anyone. Take a break, or try playing a different genre. I find that if I'm bored with my playing, if I just take a few days off from playing I come back to it with more interest.
Stop playing for money for a while and just play for fun. A lot of times, lack of ambition is because you've sucked all the fun out of something you liked to do, due to monetary reasons. Hook up with a ska band, they're normally fun people to hang out with. If you're having fun doing what you're doing, your mojo will come back. Or, spend a lot of time going to local gigs and concerts for other groups, and see if there's a sound you like. Nothing brings mojo back like true inspiration, and a good way to get that is exposure to new things.