Synonymy is important but difficult for language learners to grasp. Using a forced-choice question instrument, along with corpus data as reference, this study examines the use of four sets of synonyms by intermediate/advanced Chinese EFL/ESL learners and native English speakers. The data analyses reveal several key findings, including a general synonym acquisition trajectory. First, synonyms are often differentiated by their typical collocates; hence, the acquisition of synonyms is largely the learning of their salient collocates. Secondly, construal of the communicative purpose/context at hand also plays an important role in synonym selection. Thirdly, EFL/ESL learners begin to show some grasp of the salient usages/meanings of synonyms, and their grasp of synonyms advances significantly as their English proficiency increases to advanced level, but advanced learners still exhibit difficulties in synonym use, including an inadequate ability in forming context-called-for unique construals. Fourthly, frequency plays a crucial role in synonym acquisition, as low-frequency synonyms and salient synonym collocation usages with a low raw frequency are especially difficult for L2 learners. Implications for pedagogy and future research are also discussed.