textbook says 未婚 is single but that feels wrong??

so my book says 未婚 is just 'unmarried' but like... is it? i told this Japanese guy I was 未婚 and he looked so confused lol. like maybe he thought i meant I was a 職員 or something?? wait no thats staff. i mean 自由! like free? anyway is it like SUPER formal? because now im thinking of like the lower house 下院 or something crazy. wait what was my question again? oh yeah can you use it on tinder or is that weird...