Answer: underestimating

AnswerCrossword Clue
UNDERESTIMATINGNot sufficiently concerned about
underestimatingRegard (someone) as less capable than they really are
underestimatingUNDERESTIMATE, to estimate as being less than the actual size, quantity, or number
underestimatingEstimate (something) to be smaller or less important than it actually is