This　article　primarily　studies　the　adaptive　output-feedback　consensus　tracking　control　issue　for　nonlinear　multiagent　systems　(MASs)　with　unknown　control　directions　against　deception　attacks.　First,　a　composite　observer　combining　the　state　observer　and　the　disturbance　observer　is　developed　to　concurrently　estimate　the　states　of　confronting　deception　attacks　and　unmeasurable　disturbances.　Moreover,　to　resolve　the　unknown　gains　resulting　from　deception　attacks,　the　adaptive　attack　compensator　is　proposed.　Furthermore,　in　view　of　the　logarithm　Lyapunov　function　in　the　final　step　of　the　design　process　and　the　intelligent　approximation　technique,　a　new　composite-observer-based　adaptive　consensus　tracking　control　strategy　is　constructed.　The　suggested　control　strategy　ensures　the　boundedness　of　all　the　closed-loop　signals　while　also　achieving　synchronous　tracking　of　the　leader＇s　output　by　the　followers.　Last　but　not　least,　the　effectiveness　of　the　suggested　control　strategy　is　validated　through　two　simulation　examples.