The store owner kept awaryeye on him.The underlined word is a/an -

Adjective: 
- যে শব্দ Noun/ Pronoun এর দোষ গুণ, অবস্থা, সংখ্যা, পরিমাণ ইত্যাদি প্রকাশ করে তাকে Adjective বলে।
- যেমন - Some water, A little oil, Cold winds, horrible storm ইত্যাদি।

Wary [ওএআরি] (adjective): 
English Meaning: Careful when dealing with somebody/something because you think that there may be a danger or problem
Bangla Meaning: সতর্ক।

Synonyms: Cautious (সতর্ক), Careful (হুঁশিয়ার), Alert (সাবধান), Attentive (একাগ্রচিত্ত), Watchful (সজাগ)। 
Antonyms: Unwary (অসচেতন), Careless (অমনোযোগী), Heedless (অসতর্ক), Inattentive (অসতর্ক), Reckless (বেপরোয়া)। 

Other Forms:  
- Warily [ওএআলি] (adverb); - Wariness (noun).
Example Sentence: 
1. She was wary of getting involved with him.
2. The store owner kept a wary eye on him.