slap-happy

adj (infml 口) cheerfully irresponsible; carefree 马大哈的; 粗心大意的; 无忧无虑的: too slap-happy in his attitude to schoolwork（他）对功课太马大哈.

slackly, slackness, slag, slag-heap, slain, slake, slalom, slam, slander, slanderer, slanderous, slanderously, slang, slanginess, slangy, slant, slanted, slantingly, slantwise, slap, slap (also ,slap-bang), slap-up, slapdash, slapstick, slash, slat, slate, slattern, slatternliness, slatternly, slaty, slaughter, slaughterhouse (also abattoir), slave, slave-driver, slave-trade (also `slave-traffic), slaver, slavery, slavish, slavishly, slay,