This study examines the productive knowledge of synonyms in English by 40 Saudi EFL learners. It also tests whether the participants' English proficiency level plays a role in their production of English synonyms. To this end, the researcher designed a translation test to measure Saudi EFL learners' ability to produce the correct synonym in contextualised English sentences. In order to test whether the English proficiency level of the participants influenced their production of English synonyms, the participants were divided, on the basis of their scores on the Oxford Placement Test, into two groups: 20 Advanced Learners (ALs) and 20 Intermediate Learners (ILs). The answers of the two groups on the translation test, i.e., the ALs and ILs were compared to check whether their English proficiency level played a role on their answers. A Chi-square test was employed to determine whether the differences between the ALs and ILs on the test were statistically significant. The results show that the number of correct answers provided by ALs was higher than that provided by ILs, suggesting that their English proficiency level may have played a role in their answers. The study suggested that the main sources of error were L1 interference, lack of focus on the acquisition of vocabulary in schools in Saudi Arabia, lack of knowledge of some English lexical items, lack of awareness of the different nuances of meaning between the synonyms in English and lack of knowledge with English collocations. Finally, the study concludes with some recommendations for further research.

This study investigates 40 Saudi EFL learners’ receptive knowledge of synonyms in English. It also tests whether the participants’ English proficiency level plays a role in their comprehension of English synonyms. To achieve this, the researcher designed a multiple-choice test to measure Saudi EFL learners’ ability to recognise the correct English synonym in contextualised sentences. In order to test whether the English proficiency level of the participants plays a role in their comprehension of English synonyms, the participants were divided on the basis of their scores on the Oxford Placement Test into two groups: 20 Advanced Learners (ALs) and 20 Intermediate Learners (ILs). Twenty native speakers of English (NSs) acted as the control group. The native speakers’ answers on the multiple-choice test were considered as the accurate answers. The answers provided by the ALs and ILs were compared to those provided by the NSs to determine whether the answers of the former approximate those of the latter. A Chi-square test was employed to determine whether the differences between the three groups, ALs, ILs and NSs on the multiple-choice test were statistically significant. The results reveal that the answers supplied by the ILs differed statistically from those of NSs on all items on the multiple-choice test, whereas those provided by the ALs differed significantly from those of the NSs on eight items. The results also show that participants’ English proficiency level may not have played a role in their ability to recognise the correct synonym on all items on the test. The researcher argued that the main sources of error were interference habits from the participants’ first language (L1), lack of awareness of the semantic differences between the synonyms in English and lack of familiarity with English collocations. The study concluded with some pedagogical implications for ESL/EFL teachers in the context of teaching English synonyms to L2 students.