There are nearly 400 words that match, here are a selection:
Four letter words with the same first and last letter are:areaariaaquaaurabarbblabblobbulbchicdeaddeeddieddyedeaseeaveedgeelsefiefganggonggroghashhighhushkickkooklolllullmaimneonnoonnounoleoontoOreoorzoouzopeeppimpploppomppoopprepproppulppumprearroarsanssasssoustacttartteattauttenttesttextthattilttintToottorttouttrottufttwitwhew
Ache, achy, ashy, echo, john and oohs are 4 letter words. The 3rd letter is H.
shut shun crud spud drug glut
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern --A--W. That is, six letter words with 3rd letter A and 6th letter W. In alphabetical order, they are: leasow meadow reavow shadow
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern -TR----A. That is, eight letter words with 2nd letter T and 3rd letter R and 8th letter A. In alphabetical order, they are: atrophia strobila stromata strontia
List:BajuDojoFujiGajoSojaSijoThere we are. They sound weird but they are English 4 letter words with 3rd letter 'j'.
afar
Lulu
You can not spell any 4 letter words with the 3RD letter N using only the letters pmhlijkssxt. The letters do not include the letter N.
Four letter words with the same first and last letter are:areaariaaquaaurabarbblabblobbulbchicdeaddeeddieddyedeaseeaveedgeelsefiefganggonggroghashhighhushkickkooklolllullmaimneonnoonnounoleoontoOreoorzoouzopeeppimpploppomppoopprepproppulppumprearroarsanssasssoustacttartteattauttenttesttextthattilttintToottorttouttrottufttwitwhew
Ache, achy, ashy, echo, john and oohs are 4 letter words. The 3rd letter is H.
shut shun crud spud drug glut
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern I-I--A-. That is, seven letter words with 1st letter I and 3rd letter I and 6th letter A. In alphabetical order, they are: initial irideal iridial iridian
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern --I-AI-. That is, seven letter words with 3rd letter I and 5th letter A and 6th letter I. In alphabetical order, they are: abigail huitain kaikais zaikais
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern --A--W. That is, six letter words with 3rd letter A and 6th letter W. In alphabetical order, they are: leasow meadow reavow shadow
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern --T---I. That is, seven letter words with 3rd letter T and 7th letter I. In alphabetical order, they are: astatki intagli matsuri vitelli
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern --G-I. That is, five letter words with 3rd letter G and 5th letter I. In alphabetical order, they are: aggri logoi pagri segni