Arabic vocabulary learning can become more contextually meaningful when learners are given opportunities to identify lexical gaps and ask about words drawn from their everyday experiences. This study examines how curiosity-related inquiry, student-generated questions, vocabulary recording, peer noticing, and multilingual mediation interact in Arabic vocabulary learning at a Malaysian Islamic school. Using a qualitative case study design supported by descriptive learning evidence, the study involved 60 Form Four students aged 16-17 years at Maktab Mahmud Yan, Kedah, Malaysia, during a two-month program from November to December 2022. Data were collected through participant classroom observations, students’ vocabulary logs, documented questions, teacher field notes, and informal student responses, and were analyzed primarily through inductive thematic analysis. The findings show that student-generated questions made lexical knowledge gaps visible and connected Arabic vocabulary with familiar objects, actions, routines, and local expressions. Vocabulary logs enabled individual questions to become shared lexical input, while approximately 1,200–2,000 recorded items represented accumulated lexical exposure rather than vocabulary mastery. The multilingual setting also required Indonesian teachers to negotiate meanings across Malaysian Malay, Indonesian, and Arabic before providing appropriate Arabic equivalents. Arabic verbal appreciation was associated with greater observable willingness to ask and participate. The study highlights student-generated inquiry, lexical documentation, peer noticing, and multilingual mediation as interconnected processes in contextual Arabic vocabulary learning.