探
tàn · HSK 7
visit
🔦 扌hand + deep-pit phonetic = a hand groping deep into a cave to feel around = probe, explore
The 扌hand radical plus the right side (shared with 深 deep) gives the sense of a hand reaching deep into something to search by touch. Sound tàn rhymes with the start of tangent, a line that stretches forward to just touch a curve.
探 — hand radical 扌 + 罙 (depth/cave)
探 combines the hand radical 扌 with 罙, which depicts a hand reaching into a cave or deep place. The original sense was reaching in to feel for or retrieve something hidden, which extended to 'probe,' 'search,' and 'explore.' 罙 also hints at the sound.