We present a detailed theoretical study on electronic and magnetic properties of Mo nanowires with different structures. The ultrathin nanowires of this 4d transition metal show a unique behavior for the stability. We notice that zigzag structure is stable at the lower values of nearest neighbor distance. On slightly stretching the nanowire, the ladder structure is preferred while the dimerized structure, with the highest value of cohesive energy, is the most stable structure at larger nearest neighbor distances. This work suggests that magnetic ordering of Mo nanowires can be tuned with structure. The linear and ladder structures of Mo nanowires show antiferromagnetic ordering. Equilateral zigzag structure prefers a nonmagnetic state whereas the planar zigzag structure is ferromagnetic. The dimerized structure stands out showing degenerate nonmagnetic and ferromagnetic states. The highest value of magnetic moment (~1.16 muB/atom) is predicted for linear chains. Relative break force values suggest that these nanowires would be difficult to be realized. The density of states and band structure shine light on engineering the electronic properties with structural tailoring. We notice that dimerized structure is the only one which can be used in semiconducting applications with a band gap of 1.1 eV. Interestingly, all these Mo nanowires show a signature of covalent bonding coexisting with metallic charge sharing, the former getting enhanced with the stretching of the wire.