How many letters does the top answer for “showing unfeeling resistance to tender feelings” have?

The most common answer is flint (5 letters).

Crossword clue: showing unfeeling resistance to tender feelings

3 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

flint 5 letters wn-def

a hard kind of stone; a form of silica more opaque than chalcedony

flinty 6 letters wn-def

showing unfeeling resistance to tender feelings

obdurate 8 letters wn-def

showing unfeeling resistance to tender feelings