He is rough around the edges, but he has a kind heart.
He held out the teacup with clumsy, unrefined hands.
Standard kanji spelling. The 武 (martial) component suggests a rough, unpolished quality.
Alternate kanji spelling using 無 (without) instead of 武 (martial). Less common than 武骨 in modern usage.
The reading ぶこつ arose by reading the spelling 無骨 on’yomi; that spelling had represented こちなし, “uncouth, tactless.” 武骨 is a variant spelling, and the modern word denotes roughness or lack of refinement.