amateurish (adj.)

• amateur
• clumsy
• crude
• defective
• deficient
• dilettante
• dilettantish
• faulty
• flawed
• green
• half-baked
• immature
• raw
• sciolistic
• semiskilled
• shallow
• superficial
• unendowed
• unfinished
• uninitiated
• unpolished
• unprepared
• unprofessional
• unschooled
• unskilled
• untalented
• untaught
• untrained
• untutored