How many letters does the top answer for “unskillfulness resulting from a lack of training” have?

The most common answer is maladroitness (13 letters).

Crossword clue: unskillfulness resulting from a lack of training

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

maladroitness 13 letters wn-def

unskillfulness resulting from a lack of training

slowness 8 letters wn-def

unskillfulness resulting from a lack of training

unskillfulness resulting from a lack of efficiency 60% similar → inefficiency