Arylamines (like aniline) are less basic than alkylamines. In arylamines, the $-\text{NH}_2$ group is directly attached to the benzene ring. The unshared pair of electrons on the nitrogen atom is in conjugation with the $\pi$-electron system of the benzene ring and is thus delocalized through resonance. This decreases the electron density on the nitrogen atom, making the lone pair less available for protonation compared to alkylamines, where the alkyl groups exert a +I (electron-donating) effect, increasing the basicity.