Headmonishedthem for stealing and told them it was a great sin to steal apples from his orchard. The underlined part is -

• He admonished them for stealing and told them it was a great sin to steal apples from his orchard. The underlined part is - Verb.

• Admonish (verb transitive)

English Meaning: To warn someone not to do something, usually in a kind way, or to tell someone to do something.
Bangla Meaning: (আনুষ্ঠানিক) মৃদু ভর্ৎসনা/তিরস্কার করা; সতর্ক করে দেওয়া: The workers were repeatedly admonished for being late.

Other Forms: 
- Admonition [অ্যাড্‌মানিশ্‌ন্‌] [Uncountable noun] মৃদু তিরস্কার; ভর্ৎসনা; হুঁশিয়ারি; সতর্কীকরণ।
- Admonitory [অ্যাড্‌মনিট্‌রি America(n) অ্যাড্‌মনিটোরি] (adjective) মৃদু ভর্ৎসনাপূর্ণ; সদুপদেশপূর্ণ।

Example Sentence: 
1. He admonished them for stealing and told them it was a great sin to steal apples from his orchard.
2. They were admonished to take advantage of the opportunity.

Source: website Lecture.