行っていらっしゃい: alternative form of いってらっしゃい (itterasshai)

(honorific) to go / (honorific) to come / (honorific) to be

welcome / please come on in

(humble) a son (male child) / (euphemistic, humorous) penis

school (institution dedicated to teaching and learning)

to go; to come to one's place / to (a letter) be delivered / to depart / to rely (on a method) / (年が～) to age / (うまく～) to go well / イく: (slang) to have an orgasm, to come, to cum

past tense and perfective aspect of 行く (iku) [godan]

past tense and perfective aspect of 行う (okonau) [godan]

volitional form of 行く (iku, yuku) [godan]

negative of 行く (iku, yuku) [godan]