亲密无间

close relation, no gap (idiom); intimate and nothing can come between

parent / one's own (flesh and blood) / relative / related / marriage / bride / close / intimate / in person / first-hand / in favor of / pro- / to kiss / (Internet slang) dear

parents-in-law of one's offspring

intimate / close

secret / confidential / close / thick / dense

not to have / no / none / not / to lack / un- / -less

very close / no gap between them / continuously / unbroken / hard to separate / indistinguishable

between / among / within a definite time or space / room / section of a room or lateral space between two pairs of pillars / classifier for rooms

gap / to separate / to thin out (seedlings) / to sow discontent