堪 is literary and mainly appears in fixed compounds: 不堪 (bùkān, cannot bear; unbearable), 堪称 (kānchēng, can be called/worthy of being called), 难堪 (nánkān, embarrassing). Rarely used standalone in modern speech.
Earth radical on the left — solid ground that endures and bears weight. 堪 means 'to be capable, to bear, to withstand', and the earth radical signals the metaphor: like the ground supporting whatever is placed on it. Same radical heads 地 ground, 城 city wall, 块 lump, 坚 firm.
Right side 甚 supplies the sound: shèn drifted to kān with regular sh/k velar alternation in older Chinese. 甚 itself originally pictured a rich vessel of food and drink, suggesting fullness — faint semantic resonance for 堪 'capable, fulfilling a role'. Same phonetic also gives 勘 kān (investigate), 戡 kān (subjugate).
